When describing her directorial debut, Lady Bird, Greta Gerwig turns to pop music: “It’s a pop song that’s really fun to sing along to––a really great upbeat song––and then you hear it covered by someone else, slowed down, and all of a sudden you can hear the lyrics and you think, ‘Oh no, that song’s tragic.’” As creative, intuitive, and vibrant as its writer-director, Gerwig’s film stars Saoirse Ronan as the eponymous Lady Bird, a restless high school senior eager to break out of her suffocating Sacramento hometown. But the film’s beating heart belongs to Laurie Metcalf, who plays Lady Bird’s aching, outwardly reproachful mother wrestling with how to say goodbye.

“The working title for the movie was Mothers and Daughters,” Gerwig explained during a New York Film Festival talk on Monday. “To me, that was the core of it.” On the surface, Lady Bird falls in a tradition of high school coming-of-age comedies, chronicling Christine “Lady Bird” McPherson’s turbulent senior year tinged with best friend drama, boyfriend heartbreak, and college application stress. But underneath the day-to-day teenage trials, Lady Bird is a nuanced exploration of the love and loss inherent in mother-daughter relationships.

The story’s Sacramento setting lends the film an integral Californian ethos and autobiographical element; Gerwig herself grew up in the mid-California city itching to move to New York, just like Lady Bird. Together with her best friend Julie, played by Beanie Feldstein, Lady Bird meanders around the city’s wealthy neighborhoods marveling at the bright, luxurious houses. Despite a slew of mediocre grades and fluctuating degrees of motivation, Lady Bird longs to attend college on the east coast, which she has a vague notion must be a mecca of culture and sophistication. But like any 18-year-old with dreams of running away, it is the act of moving on that highlights one’s anchorage to home. As Gerwig articulates, home will often “only come into focus when you’re leaving it.”

The high caliber of the cast aided in the excavation and animation of the story. Regarding her choice of Ronan for Lady Bird, Gerwig said, “she’s so good in it that you can’t believe that’s not who she is. That’s not her accent, that’s not how she looks, that’s not how she walks. It’s so lived-in that it feels like I just went and found this girl.” Flaunting dyed red hair and punky outfits, Ronan is magnetic as an angst-ridden teen rebel seeking love and attention. “It’s an extraordinary transformation and a true transformation,” Gerwig said. “It’s not just external. She’s a real inside-out kind of actor.”

Having gotten her own start in film as an actress, Gerwig brings a uniquely personal perspective to the role of director. “The biggest thing I think a director can do is create almost a bubble of magic safety for their actors,” she said, “so that they feel safe to play and bring their whole selves.” Using her own experience with directors as a guide, Gerwig reflected that her directing approach hinged on allowing the actors to “feel that they own those roles––the minute that they start rehearsing, they know more than I do. I do not hold the secret key of who the person is, they do.”

One technique Gerwig innovated to foster this sense of ownership was having her costume designer build wardrobes for the characters instead of specific outfits. On any given day, Gerwig said, she would present a closet of clothing options to Ronan and say, “This is what’s in [Lady Bird’s] closet, what does she want to wear today?” Another acting exercise that Gerwig utilized––adapted from Mike Mills, who directed Gerwig in 20th Century Women last year––was holding impromptu dance parties with the cast. To alleviate any awkwardness between Ronan and Lucas Hedges, who plays Lady Bird’s boyfriend, Gerwig “had them dance to Blink 182. It just made them feel unembarrassed in their bodies and their impulses.”

Though this is her first time as a director, Gerwig says she felt a desire to write and direct from a young age, and was grateful to have female filmmakers like Claire Denis and Chantal Akerman as models of success. “The very first film that I fell in love with that made me understand cinema was Claire Denis’ Beau Travail. I didn’t know that it was directed by a woman until the end,” Gerwig said. Even with a strong foothold in the industry and years of production experience, Gerwig said, “you need to have examples that you can dream towards––it’s very hard to create a dream without examples.”

With Lady Bird, Gerwig hopes to encourage the proliferation of women in film, both in front of and behind the camera. In a way, it’s an answer to the dearth of films that explore female coming of age in an authentic way. As Gerwig puts it, she considered the questions: “What is Boyhood but for a girl? Or what is 400 Blows but for a girl? What are these stories, and not ‘does she date the guy,’ but ‘what is personhood for young women?’” Looking to the women in the audience, Gerwig said, “I want the women right now to see this and make their own dreams for themselves.”