Jailbait Babysitter(1977)

Vicki is seventeen and her older friends call her Jailbait. Her boyfriend Robert is frustrated because Vicki doesn't want to do the wild thing, but he's willing to wait. After a party gets out of hand, Vicki escapes with the help of Lorraine, who takes her in as a houseguest. While Lorraine teaches Vicki etiquette, Robert wonders what happened to his girlfriend. And Vicki soon learns more about Lorraine's job as an "executive liaison."