Is it bad that I'm having second thoughts abt my prom date?

I asked him out, and he's a senior.. he still hasn't given me the form, but I'm starting regret having asked him! I know it sounds awful, and maybe I sound like a *****, but I'm just not attracted to him. I just asked him out in my desperation, and now I think that I shouldn't have! And now I wish I could have waited and asked this other guy.. what should I do???