Think of all the hyperverbal high school heroines who have appeared on the big screen—Ellen Page’s Juno, for example—and then consider your own adolescence. “That too-cool teen who’s able to cope with everything with a quippy little remark never felt true to me,” says the 36-year-old writer-director Marielle Heller. Her highly assured feature debut, The Diary of a Teenage Girl, which came out this past summer, presented a memorable and honest representation of girlhood in the form of Minnie Goetze (Bel Powley), an earnest 15-year-old who enjoys a prolonged sexual awakening with the 30-something boyfriend (Alexander Skarsgård) of her mother (Kristen Wiig). The film’s proto-feminist protagonist’s discovery of her own sexuality is so ribald that the movie earned the equivalent of an NC-17 rating in Britain. On the surface, Minnie has little to do with Heller’s next subject, the venerable Ruth Bader Ginsburg, who will be played by Natalie Portman in a forthcoming biopic. Still, Heller insists that there is a link between her teenage character and the octogenarian Supreme Court justice. “I love seeing how millennial feminists gravitate toward Ruth’s badass cred,” Heller says.