"What has atheism to offer to account for first things and first life ? "

Pete, the emphasis on science and cosmology is explained in detail by those who
are not of the religious persuasion necessarily. The only thing I can tell you about
"atheism" is that is supports the scientific method which has answers for first things and first life. I refer you to Neil deGrasse Tyson for a concise explanation.

"as far as dawkins is concerned ,it seems that he refuses to debate creationists"

Actually in the past, he has debated creationists. I think he doesn't do it now because the arguments for it are always the same cookie cutter rejoinders. There is no scientific
evidence for creationism since it is based on the bible. How can anyone argue realistically about something that is mythological and unscientific?

Pete, this "has a beginning" is called in logical circles the "Cosmological Argument". The natural followup on this statement is as follows: There must be something that made the "First Cause". In short, what created a god? Something must have caused a "First Cause". I advocate that humans created the notion of a god.    Science is now investigating the "Big Bang" theory and that there may have been quantum organisms
in the "nothingness" that started the advent of physical matter. We don't know all the details as of yet but there is a lot of scientific information that bears scrutiny.