You need to demonstrate that a god exists.
You should not believe stuff because it MIGHT be true.
ANYTHING MIGHT be true.
In the case of Mankind and God. what is the ANYTHING which MIGHT BE TRUE.
IT would have to include God made us. Because we did not make ourselves as the need for a man and a woman to procreate shows.
Not knowing something does not mean MAKE UP AND ANSWER. It simply means you do not know.
Why are you so afraid of not knowing?
We are not making up the answer... The tower of Babel shows how God scattered the people all over the world giving them different tongues so they could not understand each other, each to their own Country. However in every Country and even the remotest tribes found living isolated from the rest of mankind all know and believe in A God who created the world and man.
Sometimes the evidence itself, is the most astounding clues we have. That all places know of a God who created us.
Even a flood is universally accepted in the world as we know it amongst those people.
So the evidence would suggest that God was there at the beginning and that all mankind in every nation knew it.