Un Problemo para me heh heh heh ^_^!?

Okay, if you've seen my previous questions then you know that I'm crazy about this girl at school. But... every time I get close to asking her out I choke. Heck, even when I get the chance to talk to her (walking her to cl) my mind goes blank and I can only think of comical sacrastic comments when she says bad things had happened. I'm pretty sure she does like me though... she smiles alot, does this cute voice, and even pouts cutely when something goes wrong. So... yeah how can I get over this? It's funny... I give advice to other people about this same problem but yeah... as I said my mind goes blank. x_x!