I'm 32, a mother of three, and train with Corpus Christi Parkour. I'm also into archery, gaming, horse riding/training, and martial arts--I teach Okinawan Kenpo.
The people I have met through parkour have become some of my closest friends, and I'm always counting down to my next group training session. Girls, don't shy away from training with the guys. Just because they're dudes doesn't mean they're at a higher level than you, or jerks, or anything else, really, and you're not there to compete with them at any rate. You're there to help one another progress, cheer one another on, and to help each other train safely.
I love seeing so many women in parkour, and want to see us fully integrated and playing a major part in the larger parkour community.