How to overcome the 'fear' of kissing someone?

Okay, well I've kissed someone before, but at this party I'm going to, there's going to be boys there. I really like this guy who's going, but apparently we're playing some games that involve kissing? Most of the people there who are going are really popular with boys and although I know them quite well, I don't know if I want to kiss them... I think I may be frigid ? PLEASE help! :(