• Courtesy Of Marni Grossman/Amazon MGM Studios
• Maisy Stella and Aubrey Plaza play younger and older versions of one woman in this coming-of-age comedy.

This week I had a tough choice between big and small: Megalopolis, the ambitious, already somewhat notorious science fiction epic from Francis Ford Coppola; and My Old Ass, a Canadian comedy with a cheeky title. I took a rain check on the first and saw the second, partly out of curiosity and partly for its more manageable running time.

The second film from writer-director Megan Park, My Old Ass premiered at this year's Sundance Film Festival and is distributed by Amazon MGM Studios. Whether the festival pedigree and limited theatrical release (at the Majestic 10 in Williston and Capitol Showplace in Montpelier as of press time) qualify it as an "indie" these days is anyone's guess.

The deal

Elliott (Maisy Stella) is a small-town girl who can't wait to escape from her family's cranberry farm to college in Toronto. On her 18th birthday, she celebrates her freedom by hooking up with her childhood crush (Alexandria Rivera) and camping out on an island with her two best friends (Kerrice Brooks and Maddie Ziegler). When they do mushrooms, Elliott's trip takes a weird turn. Suddenly she's face-to-face with her 39-year-old self (Aubrey Plaza), who has advice for her: Be sure to bond with her family before college and avoid a boy named Chad.

Elliott blames the shrooms — until the next day, when "My Old Ass" starts calling and texting her. Maybe she should heed her future self's warnings, after all. Spending time with the fam is easy enough. But when she meets a sweet Chad (Percy Hynes White) who happens to have a summer job at her folks' farm, all bets are off.

Will you like it?

The streaming services are pioneering a new class of movies we might call "ultra-accessible indies," with Apple TV's surprise Best Picture Oscar winner, CODA, as Exhibit A. Despite its supernatural twist, My Old Ass has much in common with that movie: a picturesque setting (this one takes place on an Ontarian lake); coming-of-age themes; an outdoorsy heroine who works with her hands but dreams of a different life; and tastefully low-key sentimentality. Park's film has elements of a stoner comedy, and its title might put off some older viewers. But ultimately it's more heartwarming than irreverent: a movie for teens and their moms to watch together.

Just don't come expecting a showcase for Plaza's deadpan talents. She steals every scene she's in, but there aren't many of them. And if we have fond memories of watching Plaza burst onto the scene as a twentysomething in Judd Apatow's Funny People, we may get distracted by the lack of resemblance between her and Stella, who has a pleasant and natural but much less acerbic presence.

While Plaza came up through comedy channels, Stella looks and acts like what she is: a fresh-faced Canadian TV and pop star. That's not a bad thing, though, and she has great chemistry with everyone else on-screen, including a somewhat underused Maria Dizzia as Elliott's mom.

Teen romance can get tedious, especially when the love interest is a conventional heartthrob. White is not: His Chad is a lanky, nerdy wise-ass with a slightly androgynous quality that matches Elliott's. (Her tween fantasy, we learn in a very funny scene, was not to date Justin Bieber but to be Justin Bieber.) We savor their rapid banter even as we scrutinize Chad for signs of being someone who could eventually ruin Elliott's life, leaving her bitter and — the worst fate of all! — a nearly 40-year-old doctoral student.

Park's screenplay edges around some of the darker questions raised by its time-bending scenario. Older Elliott hints at ominous changes in her world but doesn't reveal their extent. The gorgeous, sun-washed lakescapes of cinematographer Kristen Correll convey a premature sense of loss: Elliott might never have it as good again as she does at 18. But the movie doesn't directly confront the issue of whether coming of age is more fraught now than it used to be.

My Old Ass is a likable movie that reaches out to older generations with its themes of nostalgia and regret and to Gen Z with its refreshingly accepting attitudes around sexuality and gender identity. (Elliott is bi and proud of it, after she gets over the initial shock of her own interest in sex with a boy.) The movie pulls some punches, but it makes a nice palate cleanser after last week's The Substance, a much bleaker vision of a woman's younger and older selves coming face-to-face.

Here, one of the first things young Elliott requests from her older self is a kiss. It's an inappropriate ask that rips the fabric of space-time, but there's something to be said for self-love.

If you like this, try...

13 Going on 30 (2004; Kanopy, rentable): With its time-collapsing premise, My Old Ass explores some of the same territory as the body-swapping comedies of yore. This female take on Big, starring Jennifer Garner and Mark Ruffalo, is worth a watch.

Eternal Sunshine of the Spotless Mind (2004; rentable): Michel Gondry's cult film confronts the same philosophical question as My Old Ass: If we could revise our lives to avoid painful experiences, would we? Should we?

Black Bear (2020; Kanopy, rentable): If you do want to see Plaza stretch her talents — and be deliciously mean — this is your movie.