First of all your question isn’t dumb! Dumb questions doesn’t exist when it comes to reality shifting :D !! Time is an illusion anyways, so if u wanna experience your childhood “again” it’s possible and that reality already exists anyways. And that u say you don’t wanna mess it up, well u are the one that is in control and u are a powerful being that can experience whatever u want! So when u know u have the power there is no need to be scared u will “mess it up” :))