Why is my oneitis stalking me?

Hi. Im a 23 year old classic shy/sensitive nerd and theres this girl in my college who Im having a very intense oneitis with. (In my mind)

Im not sure why but one of my fellow college students seems to be radiating intense sweetness, she appears to be very openminded and bright. Shes a female nerd, a relatively rare type. I barely have balls to even look at her, let alone have a long conversation as I consider myself to be too ugly/too unworthy.

Yet it appears that shes stalking me. I have a parttime job at a local small company and she has applied for a job there as well. She saw me exit a gym once and the next week she joined the gym. I see her way too often on the street where I live where she likes to 'walk'. Back in college she very often takes her seat near me and opens a conversation. What should I do with her? I cant believe she could be interested in me, I think shes a prank looking for validation. I know that oneitis almost always gets rejected and I think all she wants is validation.

Whenever I meet her with her friends (she has a flock of sattelite males around her, all waiting for their "chance") they laugh at me behibd my back.

On another hand, I really enjoy having this highly iltelligent girl's attention and her 'chasing' me, so if I do ask her out and get rejected then I will lose her and all the energy I have been getting from her persuit.

What to do?