Some people are wonderful at abstract conceptualization. I admire the founding figures of 20th century physics, the Schrodingers, Diracs and Einsteins. I do not have too much trouble at least starting to get my head round Quantum Mechanics and General Relativity, and I understand the magnificence of their correlations with directly observed simple phenomena such as atomic spectra and time dilation.
However, Big Bang cosmology seems to require philosophical abstractions of such a degree that we have completely lost touch with everyday reality.
We conceptualize out from a zone of familiarity. Our zone of familiarity from birth entails 3 spatial dimensions and a consciousness that registers time as a dimensional one way arrow experienced as an infinitesimal 'position', our ever present instant. We draw back our every abstraction and equate it to this familiar framework.
Space Time expanded from a singularity, we are told. Where exactly was the singularity? What did space expand into? Expand is a term which assumes the existence of space. Time 'started'. Start is something that happens at a point in time. How can time start? What was there before time? What does before mean if there is no time?
If my statements are meaningless, then so are these terms when used by cosmologists.
Bottom Line: The created cannot conceptualize the Eternal and Infinite.