Don't believe that paintball is a mans world
It's only a mans world in the sense that the world is a mans world
Be yourself, get out and play and you will be in a paintballers world, the only difference between the sexes is that certain people may look on you as a 'weaker' player because you're a girl.
You have two options - take advantage of their ignorance and beat them, or show them you are as good as anyone else
You may not be as good as other players present - but that will be you as an indiviudal & a new player, nothing to do with sex
Contrary to popular belief in some circles female players are not so much of a rare breed