“You have wings. You must learn how to harness them,” the 14-year-old protagonist of “Catherine Called Birdy” is advised midway through the Medieval coming-of-age pic. Delightfully brash and at times laugh-out-loud funny, the self-assured PG-13 comedy sees writer-director Lena Dunham harnessing her own wings, bringing her distinct voice to an unlikely setting and genre. The “Girls” alumna has made a children’s movie, a bona fide crowdpleaser about a 13th century teenager.

One of our most anticipated titles of the Toronto International Film Festival, we hoped that “Catherine Called Birdy” would offer “tween girls the adventure-filled non-fairytale they so deserve,” offering an “irreverently honest [take on] how very un-Disney life was for young women like Birdy, from the literal grit and grime, to the danger of being married off on a male guardian’s whim.” Ultimately, we were dreaming of a “feminist folktale mothers can feel good about showing their daughters.”

It delivered.

“Game of Thrones” star Bella Ramsey stars as Birdy, a rebellious teen who is precocious but has plenty of growing up to do. With his family’s financial situation in dire straits due to his overspending, Birdy’s father, a hilarious Andrew Scott (“Fleabag”), decides to marry Birdy off to a wealthy suitor, a plan Birdy finds wholly unacceptable. With creativity and gusto to spare, Birdy finds ways to drive her would-be husbands away. “I am, thank the Lord, very cunning,” she admits. “Most girls are, though we’re not given due credit for it.”

Introducing the film at TIFF, Dunham cited the source material for the film, Karen Cushman’s award-winning 1994 YA novel “Catherine, Called Birdy,” as her favorite book from childhood, and her affection for the text is palpable. The eight-time Emmy nominee seems to be having the time of her life bringing this boisterous adaptation to the screen, basking in the opportunity to tag along on her heroine’s journey, ensuring that she harnesses her wings and soars. “You don’t get to decide who we are, where we go, or how much we cost like we’re just things — we’re not things,” Birdy proclaims at one point. “We’re people, and we can think, and we can hear, and we can feel.” It’s the kind of impassioned speech that would make Jo March proud.

“Catherine Called Birdy” is now in theaters and launches on Prime Video October 7.