First date with a girl... NERVOUS????

She's a , I'm "bicurious" ... I'm really nervous, because she's shorter and pretty butch, and I'm taller and more femme. I know it sounds stupid, but I guess it's a comfort issue. Any tips, advice, anything?? I just need some help here to relax a bit! On msn we were flirting and she was talking about how she really wants to kiss me... But I'm used to kissing taller people. Oh whatever, just say something to ease me please...