Wrong XXX. When Augustin said that not more than “6000 years have yet passed,” he was referring to all of creation. Where he differed from biblical creationists is that he thought creation occurred in an instant, whereas biblical creationists believed creation occurred over six Earth days.
Why wrong? He says that right in your quote “the nature and origin of the human race”.
And yes, he believed it happened in an instant. My point is why should I believe you and not him? You’re not claiming to be infallible on your interpretation of Genesis 1 are you?