I guess I'll "revise and extend my remarks." In my mind, I place the roots of modern civilization in Mesopotamia, where we have the earliest evidence of agriculture, which I consider the dawn of civilization. Everything else before that was hunter-gatherer even if the people lived in communities. Caves, huts, teepees, stone homes, I don't care. It wasn't civilization until agriculture, in my estimation.
Arguably, it can be considered to have occurred before then. Maybe it was when language was standardized within a large group of people. Not any good way to date that.
Dr Oppenheimer and Dr Schoch have changed my opinion. (Both have books on the subject). They both think the Sumerians were refugees from Sundaland that went underwater at the end of the Ice Age. (Sundaland is the area around present day Indonesia, etc.)