What was the name of this 80's movie?

In the beginning it shows a girl hitch hiking, and as a semi truck is about to go by her, she flashes him, and he stops and gives her a ride, and then there's another girl who's always moving because her father doesn't like it in certain places, and she has to leave her mother because of him. Then in the middle of the movie her dad lets the girl who had hitched hike into his house in California with them [she's his niece]. And she wants to become a nurse, so he gets her into college, while her father supports her and the girl and dad. Then the girl whom is with her dad meets this boy. And when they wait for the girl to get out of working, she decides to have with him just to loose her virginity. Then towards the end she has to leave again, because the girls uncle put her father down to many times, and so she stabbed him in the leg with a fork. Please tell me the title :[! Oh and the guys niece had a vibrator that she gives to the girl, and she decides to experiment, and uses it in the bathroom. [IT WAS MADE IN THE 80'S] I believe.