My advice is this. For Christ's sake, don't write a book that is suitable for a kid of 12 years old, because the kids who read who are 12 years old are reading books for adults. I read all of the James Bond books when I was about 11, which was approximately the right time to read James Bond books.
Terry PratchettIt was sad music. But it waved its sadness like a battle flag. It said the universe had done all it could, but you were still alive.
Terry Pratchett