I am having a fucking weird start to a relationship here, and would appreciate some help. I met a girl in class three weeks ago. She seemed totally cool, and we had the same interests. We made plans to see each other.

Because of both our schedules, we weren't able to meet up. I thought about her alot. I tried texting/talking to her a couple times, but she wasn't very responsive. Then sometimes out of the blue she'd start talking to me, then stop just as suddenly as it started.

So tonight we finally meet up at a dance party. I'm totally stoked to see her, and she's obviously REALLY excited to see me. So we talk for a little bit and end up drifting in other directions. I look around and I see her dancing with this other guy. So I think wtf? but I honestly have no problem with it since I barely know her. I do some dancing myself and we meet back up towards the end. The whole time we were together, she's acting VERY affectionate, holding and kissing me, etc.

One last thing- this girl is incredibly beautiful. Near-perfect 10. When I was with her, people would come up to me afterwards and say "Man, how'd you score that?!?" Personally I feel she is far out of my league, but I'm giving her absolutely no reason to believe that herself.

TL/DR: Incredibly hot girl seems really interested in me sometimes, sometimes not. What do I do?

meh.
another guy is chasing her. maybe she came to the party with him. she cant ditch him

she her again. she seems interested

fucking obvious

she wants you, she only drifted away to make herself seem less keen because she was losing the upper hand by declaring herself so openly?

"decode"? Oh well there's your problem right there; you're a faggot.

She likes you and go for it.
Also post some pics of her.

The problem is that I don't have much experience with girls out of my league. Any tips?

I can't help you much since personally I cannot even get girls within my league (I think that means they are out of my league right?).
But I can advice you to be confident with her. Confident enough to show her that you are within her league.

This.

She's obviously interested, you guys were not only dancing but kissing?

Your halfway there. People dance with everyone at parties unless she was all over the other guy too, I'd say your already in.

Just be yourself and continue doing what you've been doing, it appears to be working.

Decode her...No fuckin' problem dude....

She's a pain in the arse. Simple.

The whole "hard to get thing" is hit or miss. Considering she's really good looking she's just used to men falling over themselves to please her and she's most likely around far more experienced dudes than you. Dudes with more "game" if you will. It's likely that you just aren't showing her you like her in the way shes used to.

Don't let this deter you. Everyone is inexperienced at one time or another. Just chill out, be confident (even if you have to fake it) and ask her out on a date. On the date you won't be surrounded by other people dancing and therefore not surrounded by other dudes wanting to dance with her. Take her to eat and then ask he what she feels like doing. If she says she doesn't care do NOT say "Well I don't either." Just take control and go someplace. A movie, a game or whatever. Most of all, be yourself and go with the flow.