Your children are gonna be fine, relax.
I watched this movie when I was twelve, and it didn't harm me in anyway. Look, your kid is either gonna get it or they won't. Anything that is promiscuous will likely go right over their heads until they re-watch it a few years later. But, if they do get it, then that's not the film's fault, likelihood is they probably knew what it meant before they sat down in front of the TV. I've seen so many people complain about how they put virginity in a bad light, overall it doesn't, Cher makes it clear that she doesn't want to have sex until the time is right; when she feels comfortable. She ditches the a guys that don't treat her right for someone who does. It promotes good and supportive female friendships, the things the three girls go through are pretty standard for highschoolers. Cher is good person the only questionable thing she does it attempting to alter her grades. The only scene I'd caution with is in the car after the party.