Your first kiss isn't likely to be a full-on make-out session anyways (at least mine wasn't) so don't worry too much about it. Just do what feels natural. And if all else fails, copy what she's doing until you're comfortable enough to start doing your own thing. She won't call you on it because she won't notice, and it'll keep you from doing anything she might find weird.
Jessi the Gweat and Tewwible
Do not offend the chair leg of truth. It is wise and terrible.
~Laura was here~