Down to a singularity? Isn’t that how it all began?
We’re kind of getting off-topic, maybe, I dunno cosmology encompasses humanity by definition. Let’s assume for the sake of this analogy we live in a finite universe, I think it’s irrelevant for our debate but serves to help illustrate my point. If your finite universe was a circular plane that ended at the boundary you would say that is it and then you could base the beginning of everything at the beginning of that circular plane. You would be completely unaware of the larger circle your circle was born in because all you can observe is your plane, in which you exist.
No matter where you bring a beginning to, you can always create something theoretical further back, on top of, or around the beginning of that reality.