I’d assume Harry Potter time turner rules, where there were always two of you when you were growing up, because future you had already gained immortality and gone back in time. But you never realized there was a second you when you were growing up, because future-you actively avoided interacting with past-you.

It also resolves a lot of the “what if you accidentally change the timeline and prevent yourself from ever being born” types of paradoxes, because you were already born which means anything your future-self does will automatically resolve with you being born.