college is college. In graduate school, the women usually asked me out--sort of your scenario above. But, college isn't exactly like real life. In real life, there aren't thousands of horny single 25 year-old women living, eating, studying, and working out at the same gym as yourself in a "town" (i.e., campus) built exclusively for young men and women.
Tall girls generally: A) date tall men (not often); b) don't date often because they are shy and a bit insecure (often); or c) date men shorter than they are because, as it turns out, shorter men have dicks just like taller men, and shorter men tend to be of the mindset that having a tall girl moaning for their body is, well, a huge turn-on (this relationship happens more often than you would imagine).
Anyway, just talk to all of them. One will say something back. All you gotta do at that point is start asking non-intrusive questions and she'll take care of the rest until its bra removal time