I'm one of the few people (okay, only person) I know that actually told my mom, of my own free will, when I lost my virginity. And her reaction, she jokingly said, "At least you're normal." It didn't kill me or her. But that's also just the relationship I have with my mom. Not to mention I'm terrible at lying, so if it did ever come up, she would have found out anyways. But you have to do what you are comfortable with. You're an adult, you're off at college living your own life independently, and you're parents really don't need to know everything going on in your life.

I think you should tell your parents whatever you feel comfortable telling them. They're only worried about you. You're safety is the most important thing to them, and sure, finding out you lied is going to sting, the fact that you were safe about it is more important. You've known him for years, you met him in a very public place, and I'm hoping you used protection when you slept with him. You can always just remind them that they brought you up to be a responsible adult and that it's time to start trusting you with actions and consequences. You could always throw out a joking, "Do you really want to know? Cause I sure don't want to know about what you do"

I also think it's perfectly fine to talk to him about what happened instead of simply ignoring it. I don't think you'll come off clingy. Relationships are based on communication, so learning to communicate on touchy subjects like this is only going to make your relationship stronger.