Magic is totally off limits!

I want magic, faeries, elves even dragons to be real. But such thoughts are deemed childish and silly by most people. But is it really so wrong however? Some cling to gods and holy books to explain their world. If that’s okay, why is it wrong for someone to believe in Faeries or that there are elves in the woods behind their house? When did it become okay for only some super natural things to be believed and worshiped and the rest off limits once you’re an adult?