First, this isn't a sticking point, it's one situation.
Second, it seems to me that you already know what to do, as you are saying stuff like "that probably wasn't a good idea."
Third, You need to be comfortable with yourself. I don't know how I happened upon your post, but I hope you read this: It sounds to me like you are not terribly comfortable being sexual around girls. You want to, but you aren't doing anything about it. One tip off is that you've been on the forum for 9 months, with 20 posts. If you ever have any questions or want to learn something new, of course just post it up! We're happy to help!
But that's neither here nor there. A better tip off that you're not comfortable with yourself is that people are giving you chances to show your real sexual side (ie. "I trust/like you enough to be at your house late at night watching movies with just us here, oh and would you please stay the night at my place?"), and you act uncomfortably about it.You already know all this, I think, so I won't beat a dead horse, but let me just tell you: You are a very sexual person person. There's nothing wrong with that. This girl clearly likes you. Get out there and force sexual situations. Start kissing her. NOW! As you read this!