Diana, I don't think there are any girls only avatar sites (and it is hard to regulate who behind the screen is actually a male or female), but there are certainly websites that try to cater to the stereotypical girl. For example, Dress Up Games for Girls - Stardoll | English is a website whose target audience is girls. There are "clubs" that you can join on that website, which contain forum-like conversations. But before you join, note that a lot of members are super young on that paper doll website.