I believe that God created the entire universe and evidence suggests it was many billions of years ago and nothing in the Bible says that the universe is only a few thousand years old.
How do you suggest that God “created” a universe that always existed?
I don’t. Other than that, as I mentioned, assuming God created the universe at any finite point in time, thousands or billions of years ago doesn’t even matter, why did the idea never occur to him in the infinite expanse of time prior to that point?