I'm a male GM. A few random comments, from personal experience.
* I've found that the best groups, for me, have at least two of each gender. The difference between one girl and two girls, in terms of the power dynamic, is
huge. Of course, a pair of girls can screw this up by being catty with each other, but my experience has been that that's actually pretty rare. Moving from 2 to 3 girls, or 3 to 4, doesn't seem to have nearly the same impact.
* I started GMing when I was 12 years old, after about a year and a half of playing. I'm a damned fine GM. Playing occasionally can help retain knowledge of the 'other side of the screen', but is not really essential to the GMing skills.
* GMing for the first time is hard. Players have a hard time adjusting to another player suddenly being the GM, unless there is some mitigating factor, such as a group that swaps GMs a lot or an already established group GM who
strongly sponsors the new one (and by that, I mean plays in the game, helps run herd on the players, argues for 'the Gms word is law', etc.).
* About a sponsoring GM: I've done this for a few players that I thought had a lot of promise as GMs. Didn't always do as well as I would have wanted - one female GM in particular, I really wish I'd had another group at the time, because she rocked, and they just killed her enthusiasm for it. Ziona's story isn't unique by a large stretch, and that sucks.
* To return to the topic at hand, my first suggestion is always to talk about it with the group. Taming them a second time may not be as difficult as the first. And if you continue to be uncomfortable with them... finding a new group, or creating one, isn't as hard as you might think

.
* And remember that GMing is a Calling. Sometimes you just have to go into the den of beasts and fight the dragon so you can consume its heart and grow stronger thereby.