jumping back in

I am a 22yr old Male been out of the dating scene for a while now she is 18 yr old female. I stopped looking for a girl about 2 or 3 years ago. I had just finished taking a test in my A&P class and walked out side when one of the prettiest girls starts talking to me and she introduces me to her friends. We smoke a few cigarettes and talk for 3 hours she didn't even notice when her friends left. Since I'm a shy guy I chickened out when we said good bye.

3 weeks later same scenario we finish a test and hang out but this time we go to her car, her friend comes along but she told him that there was no room and we sat there going through each others Ipods when we realize we have the same taste in music. We sit in her car for 3 hours talking and awkwardly flirting (Me). Once again i chicken out on asking for her umber but she took my phone and friend-ed herself on facebook.

Flash to today, we get out of class and immediately start talking she has a test to study for bu asks me if I will keep her company, so I do. we start talking about all sorts of randomness. I talked about how ice skating in Chicago winter is the best winter first date because it gives you a reason to hold her hand. Sex comes up, we joke about oral and favorite positions. Finally i work up the courage to ask her for her number. she has her face buried in her book, looks up gives me a coy smile and gives me it. she gets out of class and tells me she thinks she failed her test. I say you did fine. I ask her if she wants to bet on how she did, she asks what are the terms, i say if you passed we go ice skating. she tells me that she senses something is up and its not all that innocent, i agree and say what if that was my plan. she says ok so were gonna go ice skating but what about the bet. she brings up the conversation about sex if i win i get a bj, if she wins i go down on her. then she asks even if I (me) win would i go down on her. we talk more then she passes out. I am confused shy and don't know what the hell to do i feel like im in the movie shes out of my league. all of my friends congratulate me on how attractive and cool she is, but i've been out of the seen so long i feel like i am lost.

TL;DR met a girl who is a solid 10 that is for some reason attracted to me and i have no clue what to do