but I only know this universe earth? or all the universes are in this earth too, just we can't see it?
Better ask: what could happen if I rebirth in a past moment, before I know my actual "me" and I would change something and will affect me in present. Maybe will transform me into a cat or a butterfly or a tiger. Is not obligatory to rebirth into a same human body. You can be a tree.
I don't want to change anything, and don't want to be anything but human 😂 I'm happy being me now, but I should learn better how to mature myself.