No, she was not. See the Related Link below for the imdb (Internet Movie DataBase) entry for Fast Times at Ridgemont High (1982), including a list of the full cast and crew.
Although no one won an Oscar for their work in Fast Times at Ridgement High (1982), the star of the film Sean Penn has won two Oscars since then: Best Actor in a Leading Role for: Mystic River (2003)...