Fangirl

A girl (for male version see fanboy) who is obsessed with something, ie anime (an otaku), books, or movies. Some are insane (literally) while most actually suffer from bullying, depression, social anxiety, etc, and try to block out their own lives using fictional universes. (And some are perverts. But we all know that because yaoi and yuri exist)

Maria is a secret fangirl. At school, she acts shy and normal; while at home she has a thriving yaoi tumblr page.