Isekai'd in a world nobody know(The legenderies x male autistic reader)

So...You know in every isekai stories on all isekai stories the main character know a bit about the world cuz it's a game he played or something. Well in this one your totally new. You died and got revived in another world that is totally unknown to you and you have returned to your apperence you had when you were 15 years old. But despite this you join a group of adventurer and the entire world was turned back into kids.