Cosplay whoever you like! =P The most I ever get antsy with specifics is height. Since I'm on the taller side I avoid short/cute characters. Other then that, I do whatever I like despite gender, eye colors, weight, whatever!
And now would be a great time to get into Sailor Moon as they are about to start the remake this year!
Edit: If you decide to do Aisha, let us know! The bigger the group, the better it is!