I joined my first RP site when I was thirteen. It did not go well for me. I stopped role-playing for a long time because I assumed all sites were filled with only adults and/ or older teens that were rather pretty nasty. Then, almost four years later, I came across this site. I was cautious at first, saying that there are a lot of adults on here. I was surprised at how welcoming and kind everyone was. This is by far my favorite site.
How I see it is, yes there is some adult things that take place on this site, but it's not a consistent thing. From my perspective of course. Anything she will see on here is no worse than what she would hear from class-mates at school.
I say you should let her join, it's a great way for her to improve her writing and thinking skills. She will also make tons of friends on here, and will fit right in. Since you are worried about how much of your posts she'll see, I say just be a little more careful of what you say. Of course you do whatever you wish, but I think she will be perfectly fine if she joined this site. ^^
