10 points to best answer. any advice is appreciated?

Ok, a girl and i had a great thing going (both freshmen in college). She really liked me and i really liked her, we would spend time getting to know each other and she would ask me to walk with her to class and to dinner and such. Anyways, i was with her one night and asked her to dinner off campus, and she said yes. the next day when i asked her where she wanted to go, she said i don't care but is this a friendly date or something more, and i stupidly told her that i liked her and it came out like i wanted to start a relationship. she basically said she wasnt ready for a relationship (Yeah, no duh, we had only known each other for 10 days) but not that we would just be friends. Anyways, time passed, i got pissed off, lost 20 lbs, put on a lot of muscle, saw different girls and she actually saw me once with another girl and got really jealous. after that, in class (we have 1 class together), she started dressing really nice and trying to show off her chest to me, touching my arm to ask me a question, and being really laughy when i would tell her about my weekends and she would stare right into my eyes when we talked. then, the other day she asked me to the library (first time she asked me to go anywhere in a while) and the whole time we were there we just made jokes with each other, and we were being so loud that we got nothing done and the librarian yelled at us several times. also, she kept asking me personal questions like who i was hanging out with and if i was having fun and i told her i was really having a great time and she kind of seemed to be in shock and i asked her how she was liking everything and she was like ehh, im not really having that much fun, i don't really do that much. Anyways, our night ended in more laughs and today in class she actually walked with me after class and we actually had really good and fun conversations in class (she remembers everything i say). I truly believe she is interested, i can see it in her eyes. Anyways, where should i go from here? should i wait for her to ask me to do something or should i ask her?10 points to best answer. any advice is appreciated?
Ask her out NOw!