As the credits rolled on the New York Film Festival’s screening of Lady Bird Sunday night, a woman astutely observed, to no one in particular, “I feel like we’re all in the middle of calling our moms.”

Perhaps the film’s ability to evoke that feeling explains its runaway success on the festival circuit thus far. Lady Bird stars Saoirse Ronan as Christine McPherson—who demands others call her “Lady Bird”—a high-school senior dueling with her tough-loving mother (played with knowing candor by Laurie Metcalf), falling in—and just as quickly, out of—love, learning to distinguish true friendship from faux popularity, and dreaming of East Coast college life. While Lady Bird revels in the hyper-specificities of suburban teenagehood in the early aughts (Dave Matthews Band songs, puka shell necklaces, TV news consumed by the burgeoning war in Iraq), it also waxes universal about young love and sex, class and mother-daughter dynamics, and the ever-shifting meaning of home.

Greta Gerwig, who wrote and directed the film, is telling a semi-autobiographical story, albeit one that also slots nicely with her other on-screen work. “I think I’m interested in the moment when who you think you are begins to erode,” she told Vanity Fair on the red carpet ahead of the screening. “In Frances Ha, one seed of an idea was: when was the last great day you spent with your best friend? You don’t know when it was the last great day—you just know when you’ve never had it again. I think with Mistress America, in a way it was about Tracy, the younger character, through her eyes, seeing Brooke, who has kind of aged out of a scene . . . and with this movie, it’s about the vividness of a world that’s about to end. Your last year of high school is so vivid and so extreme, and you feel the feelings, but at the same time, you know it’s about to completely end.”

The film also marks a significant new chapter for the 34-year-old director. Gerwig, who opted for philosophy at Barnard College over film school, got her start as an actress in early mumblecore films like Hannah Takes the Stairs, and has since become an indie film staple; last year she starred in both the Jackie Kennedy biopic Jackie and the ensemble dramedy 20th Century Women. Lady Bird is Gerwig’s solo directing debut.

According to her actors, though, assuming the role of director came intimidatingly easily to Gerwig. She helped each actor have a sense of ownership over their character, welcoming, for example, Ronan’s opinions on Lady Bird’s attire. For Timothée Chalamet, who plays Lady Bird’s mansplaining crush, Kyle, Gerwig encouraged viewings of Éric Rohmer films to study “young men talking at women about their ideas.” And as a consummate music-lover, she always came to set prepared with a perfectly curated playlist.