Deadly Lessons(1995)

Ann never fit in. All through high school she was excluded and made fun of by the "in" crowd. When she goes away to college, she is shunned by a wealthy, elite group of students. Her only chance at social acceptance is her popular jock boyfriend, but the group literally seduces him away, leaving Ann lonely and bitter. Ann turns to a mysterious friend she's known since childhood--a wild woman who doesn't let people push her around, and who guards Ann from anyone wanting to hurt her. When her protector learns how Ann was betrayed, she begins teaching her own lessons in murder, mayhem and revenge.