On a chilly afternoon in the suburbs of Berlin, 19-year-old Nilab Haddadi is crying, or she isn’t. Nilab (called “Nila”), the narrator of Good Girl, won’t admit the truth, or has forgotten it.

It is not a coincidence that we discover her real name only after six chapters: Nilab Haddadi. Crushed by the pressure to be a “good girl,” she rebels with drugs and booze. But her ...