Search Results: acting like someone else

I'm kind of confused. I've been getting to know this girl for the past couple of weeks, and it was pretty good in the going. She called my laugh a "cute white boy chuckle," we kept glancing over at each other--especially when laughing at some joke or some such--finding ourselves next to each other often, and she kept touching me through arm brushing and head patting and all of that. I have to admit that I didn't return the compliments or the touches, but I did accept them gladly and didn't move away when she was touching me. In fact, I was going to ask for her number yesterday, but then she started acting extremely strangely.
Yesterday started pretty similar to the other days; we kept glancing over at each other despite being at opposite ends of the classroom. I was going to ask for her number as I was walking with her down the hall, but I wasn't able to because she decided to leave with someone else. That was fine, I thought. But during the next class we had together, she kept going over to other boys at and behind our table and touching all over them and talking vehemently with them, while just completely avoiding me conversationally and physically. Every time our legs touched or our arms or something like that she let them stay there for a while and then moved them away. She kept glancing over at me and staring, however, typically twirling her hair on biting on her necklace. She was pretty to the point in asking the questions I gave her as well, in stark contrast from before, but she still remained playful. Then I later saw her walking with one of my friends and brushing all over him as well. How should I proceed? I was thinking about asking her if she could help with my homework, and then ask her for her number if she says yes. If she doesn't, then I know how she feels and I don't look like too much of a weirdo.

I know I made this a poll, but please add an opinion in addition to voting. Thanks!