Happy Birthday to Me (1981)

Virginia revels in her status as part of an elite group at her private school. As her 18th birthday approaches, a series of chilling murders unfolds, claiming the lives of her closest friends. With her own troubling history of blackouts stemming from a mysterious accident a year prior, suspicions arise about her involvement. As the body count rises, the dark secrets surrounding her accident and the truth about the killings slowly come to light, leading to a shocking revelation that will change everything for Virginia and her clique.