mayb shes shy. She thinks you're fit, but like you said, you're 'way out of her league' so she is hesitant about going out with someone who is better looking/older than her.
I used to be like that, I really fancied this guy who was soo fit, but as soon as he started showing an interest in me I sort of backed off. I dont know why, Its just he sort of weird thing girls do.