Welcome to 18 (1986)

Three young women looking for adventure get jobs on a dude ranch. The film follows the adventures of three high school girls the summer after they graduate. After their jobs at a dude ranch fail to work out, the girls head to Lake Tahoe where they meet Talia (Cristen Kauffman). Talia's boyfriend Roscoe then helps the girls get a job at a casino which leads to trouble.