This story is all concept and no substance. You have an idea, which is good, but it's not enough. You need to think not just about "what," but "why" and "how" and "what next?" A story needs conflict, and an interesting resolution to that conflict - the closest thing to a problem any of the characters have is solved by a magic wish from the sky in paragraph three. This is not a satisfying plot. If you thought of things to happen in your story before you started writing, you'd end up with a better story, and as a bonus, it would solve the short-chapter problem you seem to have.