On the surface, the YA novel-turned-Disney+ movie Stargirl (featuring Grace VanderWaal as the title character) is a simple one: a confident, quirky, almost otherworldly teenage girl enters a small town high school and jumpstarts their stagnant ecosystem with her combination of generosity, limitless self-certainty, and a little bit of magic. The football team starts winning, the outcasts become popular, and shy boy protagonist Leo Borlock (played by Graham Verchere) learns how to embrace what makes him unique.

It’s a premise that can veer into the obvious, tropey, manic pixie dream girl fetishism — except that in the new film, out March 13 on the streaming service, star Grace VanderWaal (in her acting debut) forces Stargirl Caraway’s story front and center. She’s not simply a plot catalyst, she’s a fully-realized teenager whose sincerity, even in the midst of mistakes, comes into focus over the course of the film. Leo thinks she must be magic; turns out, that magic is called emotional intelligence.

“I like how humanized Stargirl is in the movie,” Grace tells Teen Vogue. “I think she's a little more fairytale feeling in the book, and the movie displays her mistakes and how she isn't perfect. Even if you're someone as cool and admirable as Stargirl, you're still going to make stupid mistakes and you're still going to have to learn from them.”

In the hands of Grace and director/co-writer Julia Hart, Stargirl transforms into a story about figuring out who you want to be and how to become that person in a way that doesn’t hurt people, but that doesn’t aim to please them either. Last year, Grace told Teen Vogue that one of the things that attracted her to the character Stargirl was that she was so “unapologetically herself.” Now, she elaborates that there’s another story lurking just below the “be yourself” narrative. “The movie also explains how everything in life has consequences,” she says, “even the things that you may think are good.”

Grace herself, of course, has undergone her own transformation, from America’s Got Talent ukulele wunderkind to major label musician slash actor slash style icon. When she hops on the phone to talk with Teen Vogue, she’s in Paris, fresh off attending Chanel’s Fall 2020 Ready-to-Wear show for Paris Fashion Week. She’s now four years on from the AGT video of her original song “I Don’t Know My Name” and has released a full-length album, 2017’s Just the Beginning, as well as multiple EPs and singles including the 2019 disco-pop groove “Waste My Time.”

In Stargirl, Grace returns to her uke roots with an original ballad called “Today and Tomorrow” that she wrote for the film. Musicality is a central part of the life she brings to Stargirl, a character who performs the Beach Boys’ hit “Be True to Your School” completely unironically at a football halftime show and inspires the long-losing team to victory. Stargirl and Leo bond over music, the love they have for old songs they learned from their parents — in particular, Big Star’s classic, “Thirteen.” Amid gorgeously-shot montages of the New Mexico landscape, she and Leo fall in first love. Even when it all falls apart, they still have the music.