Julia Hart's clever adaptation of Jerry Spinelli's fanciful novel for Disney+ is a reminder to never forget your own magic.

Who were you before the world beat you down? That so-called inner child that therapists and astrologers are always on about, how have you let them down? We’ve all let the pressures of popularity, society, and conformity mold and shape us into more palatable versions of ourselves. After all, that’s what becoming an adult is. At least, that’s what the perils of high school socialization led us to believe. How might your life have been different if someone who was so utterly and wholly themselves swooped in to remind you of your precious inner magic?

That’s the question at the heart of “Stargirl,” a tender and offbeat coming-of-age indie premiering this week on Disney+. The film is based on the 2000 novel by Jerry Spinelli, a unique young adult novelist who specializes in crafting grounded, reality-adjacent universes with a comedic flare and just a hint of otherworldliness. “Maniac Magee” and “Wringer” are two of his most lauded novels, but he also penned the tomboy-celebrating “There’s a Girl in My Hammerlock” and the ode to sibling rivalry, “Who Put That Hair in My Toothbrush?”

“Stargirl” was a mid-career hit for Spinelli, becoming a New York Times bestseller and earning critical praise for its celebration of non-conformity, long before such topics became status quo in YA literature. Julia Hart’s faithful adaptation spins the magic of Spinelli’s writing into a beguiling and visually appealing crowdpleaser with a similarly worthy message.

The story follows high school junior Leo Borlock (Graham Verchere), a music-loving free spirit who became quiet and unassuming after a traumatic run-in with some schoolyard bullies. Once an eccentric dresser with a penchant for wearing his late father’s famous porcupine tie, he quickly learned that blending in was the easiest way to avoid ridicule. But when a new student appears at his sleepy Arizona high school, she immediately catches Leo’s attention precisely for the way she stands out.

Disney+

Bearing the unforgettable, and somewhat unbelievable, moniker of Stargirl Caraway (Grace VanderWaal), she is the epitome of a free spirit. She walks around with her ukulele slung round her shoulder, and dresses in bright plaids, bucket hats, and jumpsuits. If she lived in New York or Los Angeles, she might be a fashion icon. But this being small-town Arizona, she’s a weirdo. Leo is immediately smitten, and begins following her home from school. (Not creepy at all.) Stargirl being Stargirl, she is entirely non-plussed by Leo’s awkward approach. When she discovers him crouching on the dirt road behind her mom’s car, she sends her pet rat to introduce himself.

They begin a chaste and charming romance, scored to songs by Big Star and The Cars from Stargirl’s killer vinyl collection. When Stargirl’s twee ukulele songs rouse the school’s football team to their first win in decades, suddenly everyone wants to be her friend. This is all great for Leo, until Stargirl’s growing popularity is abruptly halted by a selfless choice to comfort an injured player on the other team. Suddenly, Leo is once again hyper-visible, this time for dating a social pariah. Conforming to the pressure, he urges her: “Why can’t you be more like everybody else?” Whether she heeds his plea — and how — forms the movie’s dramatic crux.

Hart guides the actions with a sensitive and joyous hand, luxuriating in the palette of Arizona’s arid desert and gaping badlands. A beloved indie filmmaker known for festival favorites “Miss Stevens” and “Fast Color,” Hart proves that her intimate, character-driven storytelling and eye for breakout actors is a huge asset to studio fare. Hart also did a bang-up job assembling a design team: Costumer Natalie O’Brien, art director Ian Scroggins, and production designer Gae S. Buckley nailed the saturated colors and retro vibes that really make “Stargirl” sing.

The performances are grounded in naturalism and charisma, and VanderWaal is an especially exciting discovery. A YouTube star and winner of “America’s Got Talent” for her songwriting, VanderWaal brings a perfect blend of warmth and intrigue to her portrayal as Stargirl. The movie would not have worked without her. The film also features a small surprise turn by Giancarlo Esposito as a kindhearted mentor to both Stargirl and Leo. It’s a delightful change from his terrifying “Breaking Bad” days (and recent turn on prequel “Better Call Saul”), made all the more amusing by the similarities of the setting.

If “Stargirl” is any clue of Disney+’s intention to foster relationships with indie filmmakers, the burgeoning platform will definitely become a key player in keeping indie film afloat. That’s great for everyone who, like Stargirl, marches to the beat of their own drum.

Grade: B

“Stargirl” is now streaming on Disney+.

Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.