Critical response
On the review aggregator website Rotten Tomatoes, 90% of 194 critics' reviews are positive, with an average rating of 7.6/10. The website's consensus reads: "A humorous sci-fi cocktail with a twist of drama, My Old Ass doesn't throw out the wisdom with the reckless abandon of youth and the effects are hallucinogenic." Metacritic, which uses a weighted average, assigned the film a score of 74 out of 100, based on 44 critics, indicating "generally favorable" reviews.
Christy Lemire of RogerEbert.com awarded the film 3½ out of 4 stars, praising the performances, direction, and cinematography. She wrote Stella "has incredible screen presence and a great sense of comic timing, but she's equally convincing playing the more dramatic moments required of her character. It's an exciting feature film debut." Of Plaza, Lemire said she "looks nothing like Stella, which is part of the joke, but the two actresses match each other with their sardonic wit. Plaza's deadpan meets Stella's effervescence, and somewhere in that giddy mix, you quickly believe these two are one."
Lemire added, "Besides crafting characters who feel like real people, Park also creates a vivid sense of place. Much of My Old Ass is set on the scenic lakes near the family farm. Shimmering, golden afternoons on the water give way to thunderstorms thick with portent. (Cinematographer Kristen Correll creates a romantic, wistful mood throughout.) The adventures and the enveloping quiet feel personal and specific, but there's a universality to this crucial point in Elliott's life that gives the film unexpected poignancy."
Alison Willmore of Vulture wrote, "My Old Ass has the premise of a broad comedy and the soul of a bittersweet coming-of-age story. And one of the reasons that it works so disarmingly well is that it doesn't treat the former as a means of sneaking in the latter." She praised how the film "takes a grown-up's fantasy of getting the chance to retroactively apply the wisdom of your years to undo the mistakes of the past, and then turns it around to be a celebration of being young and heedless, with no clue what you're doing."
Richard Lawson of Vanity Fair also praised Stella, saying she "makes Elliott a just-shy-of-annoying good-times gal, rude and rowdy but ultimately kind and decent. It's a charming, high-energy performance that is finely attuned to the emotional undulations of the film." Lawson noted the choice of setting—"the shores and islands of Lake Muskoka in Ontario, [make] My Old Ass a proudly, distinctly Canadian film. It's as alluring as a pleasant dream, sun dappled and teeming with possibility." He concluded, "What Park creates from the tension between this joyful, exciting present and a seemingly ominous future is rather marvelous, a big and sincere sentiment about the risk and reward of life, a message that is just as worthy for a middle-ager as it is for a kid."
Filmmaker Chris Columbus named it one of his favorite films of 2024, saying "Over the past decade, I've witnessed a handful of young filmmakers with this kind of extraordinary promise. Megan, along with directors like Ryan Coogler and Robert Eggers, is a crucial component of our cinematic future. Yet she expertly acknowledges the inspiration of our celluloid past, proudly walking in the footsteps of Billy Wilder, Elaine May and John Hughes." Other filmmakers, including Kelly Fremon Craig, William Goldenberg, Drew Hancock and Don Hertzfeldt also praised the film.
