It's easier than all of that. There was no Big Bang. The Universe has existed forever and will continue to exist forever. It changes and evolves and grows larger structures. Some things get destroyed. Some things get created. But there is no such thing as creation ex-nihilo, it's more like recycling.
There was a Big Bang because we can see its remnants. But that doesn't mean it was the Big Bang - the Universe is apparently more vast than we imagined and Big Bangs might be happening all over the place, too far away for us to perceive.
Then what was that "noise" Penzias and Wilson heard in 1964?