I think someone could create a game about it , a game composed of story telling which as they progress they get to know more about different angles of bitcoin world which could be useful when they grew up 
At first, it is difficult for me to learn bitcoin. So I think, it is not suitable to teach bitcoin to a very young age child.If they can understand the basics then I guess it's alright to teach them the early, you can tell if they are interested or not because kids have more focus.