Greta Gerwig, writer and star of indie dramedies such as “Frances Ha” and “Mistress America,” marks her debut as a director in “Lady Bird,” a delightful early-2000s tale about the highs and lows of growing up.

The film fully understands it could also bear the title of “The Troubled Life of a Privileged White Girl,” but it rejects the out-of-touch, meandering hallmarks of the mumblecore genre. Instead, it keeps a laser focus on one character’s growing relationships with the people and places around her, all the while understanding her problems are minuscule in a broader context. The cast, composed entirely of brilliant and underrated actors, brings Gerwig’s script to life in a film that shouldn’t be missed.

Irish actress Saoirse Ronan stars as Christine McPherson, a California teen in her last year of high school who demands to be called Lady Bird — no relation to the former First Lady — and yes, the irony of a film called “Lady Bird” releasing in Austin the week after “LBJ” is not lost on us. Gerwig keeps the movie laser-focused on Lady Bird’s relationships with friends, family and romantic partners, but they play second fiddle to her mother, played with a raw honesty by Laurie Metcalf.

Where most cinematic mothers are either perfect angels who never make mistakes or abusive monsters, Lady Bird’s mother, Marion, is just a person. She sometimes makes the right choice and frequently messes up, but everything she does is driven by the love of her family. Gerwig’s strength lies in writing characters who feel human, characters who make mistakes and give in to their worst impulses while trying their best to do what’s right.

Ronan and Metcalf prove perfect for the freshman director, imbuing their cwharacters with humanity and displaying a complex array of emotions on their faces that can change from elated to confused to depressed at a moment’s notice. Come awards season, Ronan will likely receive the film’s largest push for accolades, but voters should not overlook Metcalf’s contribution as foil to the relentlessly hopeful Lady Bird.

As Lady Bird goes through her last year of Catholic high school, she encounters a specific combination of pressures that could only exist in this environment: to fit in, figure out her place in the world, find a boyfriend, go to college and love Jesus all at once. But Lady Bird is a rebel — she dyes her hair just because, changes her name for no other reason than that she prefers Lady Bird, smokes while eating communion supplies and refuses to listen to her parents.

Though, on the outside, she’s way cooler than any of us were in high school, she’s just as broken as all high schoolers on the inside. She puts on a facade for love interests Danny (Lucas Hedges) and Kyle (Timothée Chalamet), then comes home and gets in a passionate dispute with her mother. Lady Bird is legitimately one of the best characters of the decade, layered with a complexity very few writers can create.

“Different things can be sad, it’s not all war,” the title character says, and it’s clearly Gerwig’s mantra with the film. Sure, Lady Bird’s problems are dumb and won’t matter to her in a year or so, but when you’re 18, everything is the worst problem anyone’s ever faced. But while it acknowledges the challenges of adolescence, “Lady Bird” also does the impossible — it makes you miss high school.

"Lady Bird"

Rating: R

Runtime: 93 minutes

Score: 4.5/5