The mind’s going to boggle either way. Either the universe and time itself was created in a big bang several billion years ago, and neither time nor space existed before that, as Neil DeGrasse Tyson keeps telling us, or, as I think, there had to be, before the big bang, other big bangs, and so far back into forever, ad infinitum, turtles all the way down.
(There might also be parallel universes and stuff, but I’m not even going to get into that here. Some day, but for probably the next few thousand years or so, this universe will be enough.)
See, they keep saying time did not exist before the big bang, but I don’t see it that way. Time is a term people use for the measurement of time, which is arbitrary, but it is a man made concept for measuring something that does exist. Therefore, it exists. And since it is an abstract concept, it existed just as much at a time before matter or energy or consciousnesses.
There was one second before the big bang, and there was a hundred years before the big bang. Just because there was no consciousness to perceive it, no energy or matter for it to affect, doesn’t mean that amount of time didn’t pass, from the end of the last universe to the beginning of our own.
But, either way, there are vastnesses which are logically and emotionally incomprehensible to us. The mind boggles.