Oh my goodness, thank you so much! I so glad that you liked When She Spoke! I'm sure that you're also a wonderful writer; I've seen so many on this site already.
Personally, I don't think that age should limit anybody. You could be a wonderful writer at age thirteen, despite your lack of life experience. I've actually met people online who have published books at age fifteen, which is something that I think anybody should be able to strive for. Sites like this for unpublished books give young writers an excellent opportunity to showcase their writing and gain confidence, which opens up a whole new world for teen authors.
Fanfictionists and novelists (same thing, really) can still write worlds, even without college degrees or Caldecott medals.