“Tonight, everything changes,” Lindsay (Halston Sage) tells her friend Sam (Zoey Deutch), attempting to hype her up for a Valentine’s Day in which she expects to lose her virginity. It’s an exhortation that isn’t uncommon in movies with teens at the center, but rarely means as much as it does in “Before I Fall” since Sam is unaware that the night could very well be her last when she awakens the next morning to discover she’s trapped in a time loop where she’s doomed to repeat the day again and again. But it also can be construed as a rebel yell for its director Ry Russo-Young, the gifted filmmaker who booked her first studio gig following such introspective microbudget character studies as “Sisters,” “You Wont Miss Me” and the Lena Dunham co-scripted “Nobody Walks.”

While there’s a polish to Russo-Young’s adaptation of Lauren Oliver’s young adult bestseller that hasn’t been seen before from the filmmaker, it has the effect of actually sharpening the edge of her work, using the opportunity to watch Sam finally step back from the frenzy of high school melodrama where so much seems important when it really isn’t to observe how she figures out how she can put others before herself and realizes her own potential through repetition. Giving Sam the full width of the frame that her story deserves, Russo-Young is just as conscious of the girls who don’t receive roses from their admirers on Cupid’s Day, handed out by admirers as a high school fundraiser, as the ones, like Sam, who do, and with a nuanced script from Maria Maggenti (“The Incredibly True Story of 2 Girls in Love”), the film may run at a breakneck pace but allows for Russo-Young’s great strength of showing how people are shaped by the world around them, as characters nurse grudges that date back to elementary school and make choices between what will make it easier to fit in versus what will challenge them in ways that will make them grow.

Naturally, Russo-Young elicits strong performances from her young cast, chief among them Deutch, who wears her time-imposed burden lightly, Sage, whose Queen Bee act is tempered with great vulnerability, and Elena Kampouris, who has long been seen by Sam’s crew as the odd girl out, but what is surprising is how well her sensibilities mesh with the rigorous narrative drive, attention-grabbing music cues and the life-or-death stakes of a film designed for the young adult crowd, with naturalism setting it apart from cliche and creating a film that likely will have audiences of all ages reevaluating what’s important to them in their lives. As “Before I Fall” rolls into theaters nationwide after a well-received premiere at Sundance, Russo-Young spoke about her big step forward, avoiding confusion with her actors when shooting a film with scenes in the same location with different tones, and finding freedom in having “the film be my boss.”

Zoey Deutch in "Before I Fall"Was adaptation something new for you?

I never directed a movie that was based on a book before, so the adaptation was new and what I really loved about it was the ability to be able to look into what audiences and book fans were really responding to and just make sure that the movie was going to have that same emotional or psychological core. Tapping into what audiences were already responding to was really helpful.

What was it that intrigued you about the idea?

Initially, it was one of the few scripts that I read that really surprised me while reading it and the beginning of the movie, I wasn’t really sure I liked it – I wasn’t on board because the first 30 minutes are a little hard to take. It seems like every other teen movie. Then I found myself unexpectedly moved [by] the combination of the emotional and philosophical.

It was interesting to see since your past films often linger to see what happens in any given moment, but this has a fairly relentless narrative drive – was it an adjustment?

Honestly, it was a huge relief. I really enjoyed being able to work from Maria Maggenti’s really strong script. I love a fast-paced story and I still like it to be deep and psychological and emotional, but being able to have the plot stuff worked out already on the page and being able to dive in and do justice to the emotions of the characters, I think, was a really good combination for me.

How early did the visual ideas come for this – I love the use of the wide lens and the cool color palette?

I did a lot of research on other young adult films right now and I wasn’t into the colors – the reds and the yellows, the oranges and the pinks – of the aesthetic that always felt unnecessarily bright. This is a movie about coming into yourself and becoming who you are — these darker, teenage angsty dramatic issues, so it felt only right that the visuals had that same level of drama and darkness and angst. I also really wanted to dignify the teenage experience, so that is part of why I wanted to shoot it on anamorphic and give it a lot of scope to make it important and not shy away from the darkness. That is why I chose a horror [director of photography], Michael Fimognari, who did such a good job of making the movie not only look really big, but also making really bold choices in terms of the exposure.

Zoey Deutch in "Before I Fall"There’s a particularly striking choice of a harsh red light in the middle of the party that the film keeps coming back to – the meaning of it from being an emotional current to a warning for Sam changes throughout the film. How did that come into the mix?

For me, it was really what’s going to make that as intense and dramatic as [the scene] needs to be, but also feel realistic and unmotivated, and Christmas lights are inexpensive. [laughs] This movie looks big, but it was really shot on an extremely tight budget and schedule. When people see the movie, I don’t think they think about that, but all my years of indie filmmaking were just as applicable on this movie as they were on any other movie and Christmas lights were something I believed Kent would decorate his house with for the party, but it was also the color of anger. [laughs]

Because I’ve heard you mention the tight shooting schedule before, with this particular story where there’s a time loop, is it tricky to keep track of performances when you might be shooting a scene that’s similar in all of its physical particulars, but completely different tonally? It’s not like doing a variation on a take.

It’s really hard. You really have to know the script inside and out and every single moment where Sam is psychologically is like a math problem. I really did my homework in being organized and then Zoey and I worked together a lot to clarify every single day for her psychologically and emotionally. She really worked her ass off and [Sam is] really not an easy part for an actor. It requires a ton of range and a ton of organization to keep those days straight. [Zoey] would sometimes have to move between the different days [in the story] with very little time in between [scenes] and we weren’t always able to shoot the different days in consecutive order because of what the camera demanded, so we’d shoot day two, day four and day three all in the same camera setup, for example, in that order. Zoey and I had tricks, like naming the [different] days so we could develop a shorthand [to] be on the same page and move between the days very quickly.

She’s amazing in this. How did you know she could play Sam?

I adore Zoey and would love to work with her again. She was really my collaborator on this movie and the movie would not work without an actress as good and versatile as she is. I auditioned a lot of young women in this age range and I just felt like when I saw her audition, I felt like I wasn’t watching an audition — I was watching the movie. I was completely sucked in. She inherently understood the stakes and she’s so smart and inquisitive. She’s one of those people who just wants to get to the bottom and figure out the truth. I think the whole movie plays out on her face and it’s just fascinating to watch what goes on in there.

When I saw all the photos in Sam’s bedroom at the beginning of the film, I wondered is that time you can use to bond this group of actors who are playing best friends before shooting or is that just an extra thing that you do?

It’s a little bit of both. I wanted to have a bunch of photos with all the girls together that Sam would have on her wall, so we needed to shoot them and it was just me and all of them and we just went on this massive long photo shoot together, so it was bonding, talking about our characters, picking out outfits for them. It’s all part of the process.

Zoey Deutch and Logan Miller in "Before I Fall"As a young adult film, it would seem to be there would be a mandate for wall-to-wall pop music, but this movie uses it so effectively. Was that an interesting new tool to work with?

In the beginning, I actually had no idea that we’d be allowed to have the music that we have [because] no one thought that we’d be able to afford any of this music. So much of my process is about prep in advance of stepping on set, and there’s another director that I work with, a friend of mine who’s also a musician, who [I’d] send playlists back and forth [with] and saying, “Okay, so what songs do we need to try to get the rights to before the movie? What songs am I playing on set? And what songs am I sharing with actors?” It’s a really lengthy process of narrowing down the music, but eventually I found my dream music and put it all in the film with the editor. We never thought we’d be able to afford any of it and basically people wanted to pay for it because they became so married to what we had chosen. It just worked so well that you couldn’t imagine the movie without this music in it.

So it ended up being a wonderful thing. [The Yeah Yeah Yeahs’] “Skeletons,” for example, was a track [for the scene where Sam is] running through the forest, that was chosen before we were shooting, and I remember while we were shooting, I told the editor, try and cut this running sequence to as long as it can possibly be with that track. He showed me a cut while shooting and I was like, “Wow, that’s amazing.” And it never changed.

That scene is so great. I usually ask whether there was a particularly crazy day of shooting, but I have to imagine it involved the forest.

There were so many crazy days, I’m like, “Pick one.” That forest was crazy. There was one day where we shot all of the classroom scenes in one day and the bathroom scene. We shot all of the cafeteria scenes in one day, which was like a 12-page day. The joke on set was that every day was “Sophie’s Choice” because everyday it was like who do we have to kill to get this? It was really tough.

You wouldn’t have known it from the finished product. The last time we talked you said you learn something new on every shoot – is there something you could point to on this?

I learned so much on this. One thing that I did on this movie that I did not do on the last movie was deciding at the very beginning I was not going to care what anybody thought of me personally. I was just going to make all of my decisions in terms of what was best for the film. I wasn’t going to worry if I was inconveniencing the crew or if people didn’t like me because I needed another take. That’s not to say I was an asshole or mean to the crew, but on the film before, I think I would compromise some of my creative decisions at times because I didn’t want people to think badly of me. I was just self-conscious and worried if we had to go two hours over, everybody was going to be tired. This time, I was just like, “It doesn’t matter. All that matters is making the movie good.” I had a certain amount of tunnel vision by taking the idea of people liking me off the table, and I really think it helped. At the end of the day, all that matters is the movie and that’s what I’m beholden to.

“Before I Fall” opens on March 3rd.