I'm trying to remember the title and author of a short story I read in the 1980's in Asimov's about a teenage girl who turned into a werewolf when she got her period.
This is likely Sarah McKee Charnas's 1989 short-story "Boobs".
First publication was in Asimov's.
The story is available for free on-line, so it's easy to check, but the plot revolves around the emotional life of a young lady returning to school with visible secondary sexual characteristics, getting teased about it, discovering that she turns into a werewolf during that time of month, and finding self-worth and freedom therein. Oh, and a little revenge.
The story was nominated for the Nebula and won the Hugo and other awards.