The "art school girl" is Stone Temple Pilots frontman Scott Weiland's girlfriend from before the band formed. Her name was Mary Ann, and she did indeed go to art school. She was not, however, from Alabama - Weiland made that up for the sake of the story. She and Weiland were from Orange County, California and moved to Hollywood together. She took classes at California Institute of the Arts, and Scott got a job at a legal newspaper called the Daily Journal.
Weiland described her as his "first type-A girlfriend," and says that she set his car on fire when he tried to break up with her.