Well. Have to agree, none of us were there.
The bible maintains God was there when created the universe.
I understand that you reject the bible's record of this. I hope it works out for you.
I see that you need proof before you will believe.
I fear that no evidence that will bear enough scrutiny exists to meet your standard.
You can lead a horse to water, etc.
I doubt that you will accept that the universe had a beginning. Even though it's true.
There is an old quote:
"For those who believe, no proof is necessary. For those who don't believe, no proof is possible."
Stuart Chase