Being a kid is all about exploring and discovering the world you've suddenly found yourself in. And in the process of doing that, a child can end up developing some unusual theories about how the world works. This is particularly true in the case of how it works for them.
For instance, there was definitely a period where I was convinced I had psychic powers. I also once claimed to remember my own birth, but since my mom told me what did and didn't happen on that day when I said this, I soon realized that I was probably remembering a dream.