Is it possible to publish books under 18? Cause my cousin and a friend of mine has books that are done and they want to publish them.

Anyone can publish a book. Christopher Pauolini, the writer of Eragon got his book published when he was only 19, but he started the book when he was 15. The thing is, many young writers do not get published because the famous writers manuscripts, and more experienced writers get in first, and young writers mostly lack the experience to get published unless they have a great amount of skill. I’m not saying that it is impossible, or even unlikely, just that many other authors get in first, and if your friends or cousins book is good enough, it could get published. its all based on skill and experience, not age.