That absolutely counts. If he heard you, and didn't stop. It counts.
I don't think I'd be comfortable dating a guy who didn't listen in a situation as serious as that. You should definitely have a talk with him, and ask him if he was aware of what he did. If he was... I don't think he's worth sticking with.
When you get into an intimate situation like that, you need a partner that you trust, and that respects you. A guy that wouldn't listen when you asked him to stop is selfish and disrespectful, not to mention, breaking the law.
Something like that can be hard to get over, and it could be hard for you to trust him, or other guys, in a situation like that ever again.
If it really bothers you, it wouldn't hurt to talk to someone about it, or seek counseling. Don't ever downplay a situation like that into making yourself think that its "no big deal".
Good luck :)