Does this type of website exist? If not, would it work to make it, and how? If it wouldn't work, why not?

OK so. The regular jellies should know that I like kids and I try to be an “older sister” to the kids I know.
I always wanted a site like this when I was younger, and it seemed to never exist.
I’m thinking of a site that:
-is like Fluther. I never exactly knew how to describe it, but now that I’m on here I want something like it only for kids.
-is for kids, not just people over 13 (I know, with the COPPA it gets difficult, but I don’t think it would be that hard to do it)
-I want there to be teen-age mods, if at all possible.

Does anything anywhere near that exist? (I know about this one part of the PBSkids site is out there, called It’s My Life, but that is not what I’m talking about.) If not, would it be possible to create? If it wouldn’t work, why not? And how exactly would I go about doing this? It probably won’t happen for at least a year, if ever. But I can’t stand not knowing the answers to these questions.