I read this thread yesterday but wasn't entirely sure what to say. I'm sorry that this happened to you.

I've never dated guys, but I remember when I was young and believed I would have to. I was afraid of a guy pressuring me into something I wouldn't want to do, never mind having someone push himself on me. And the fact that I'd never been with a guy made the prospect even more scary, not that it isn't horrible when it happens to anyone.
I think what others have said about not having experience (as opposed to your girl friends) has some truth, but I'd like to add that sometimes you can just never know. It is NOT your fault for being inexperienced with dating, it's entirely on the guy who felt like he deserved to push himself on you without checking your comfort level and readiness.
You deserve much better and I hope you don't have to go through that again to find someone, male or female, who treats you with the respect that you deserve.