Hi. Girls are developing at younger and younger ages, at least in part because of hormones put into meat. Even if your daughter develops later, I am sure some of her friends/classmates will be developing soon. If you stay calm and matter of fact about it, you will be less likely to freak her out. There is a GREAT, non-religious, gender balanced book about body development called It's So Amazing. The follow up book, called It's Perfectly Normal, deals more with sex and its related issues (std's, masturbation, etc), and is designed for a slightly older crowd. Both are available on Amazon.com. You can read reviews of these, and other, books at Amazon, which may help you narrow down what you purchase. I would strongly suggest that whatever written material you provide you read first. That way you can anticipate her response, be prepared for questions, and censor anything you don't agree with or feel she's not ready for. I would also talk with her teacher or school office to see if they do any kind of lesson on development or sexual reproduction, when they do it, what is covered and in how much detail, etc. Children may see their teacher or principal as an authority figure not to be questioned; so you may need to supplement or at least be available if she has questions. I have a son who is 12 now, and about 6 months ago he came to me and said he was having a problem with his genitals (he is not close to his father and would never even consider going to him with a problem like this). He briefly described the problem, which I had never heard of and knew was not in the materials I had provided to him. He said it would be weird to show me; I offered to take him to his pediatrician (who he has seen for the last 8 years, but is a woman). I asked if he wanted to see a male dr instead, and he said that would be weird. I told him he would probably have to show the dr, and he said that was ok but asked that I step out of the exam room during that. That's what we did; she said it was nothing to worry about and gave him a cream (which I really don't think he was diligent about using). Last week he told me in a casual conversation that the problem had gone away. All of that to say that, as close as we are to our kids, there may be times when they are more comfortable with someone else. For me, it was very important to not take it personal, and to just acknowledge that my "baby" is growing up. Best of luck!