So if there is a God who created the entire universe with galaxies, stars, planets, all the life on Earth etc., why is it impossible for him to have also created fossils with the right Carbon 14 isotopes?

For the record, I'm agnostic, but isn't that sort of thing encompassed by the definition of omnipotent?

I don't believe that I've ever read or heard that a reputable theologian claimed that the world is 6,000 years old. In point of fact, most of what I've read on the subject puts the time of Moses around 3500 years ago, and Adam and Eve considerably before that.