I don't feel like a girl at all when I'm around a bunch of girls. If anything, I feel even more out of place because of how little I tend to have in common with them.
But then again, I feel awkward around a bunch of guys, but that is mostly because other people refuse to treat me like I am one of the guys. It doesn't help that I am introverted and am the type of person that doesn't speak unless spoken to.
I guess no matter what group of people I'm with, I'll always be out of place.