I know there are infinet timelines im asking were they there from the begining? and if so when did and how did we figure this out?
Well I suppose that depends on what you mean by the beginning. If you're referring to the beginning of the game, then yes. If you are referring to the beginning of the universe, that depends on whether the realities all had their own universes birthed at different times or if they were birthed at the same time.
As for how we figured it out, do you mean the realities for the Chronoverse or the Many Worlds theory itself? If the former, as I said, the details on the Reptite reality and the Radical Dreamers reality provided the evidence, though I have no idea when it was first figured out or by who.
But if you mean the Many Worlds theory...don't look at me. I have no bloody clue.