I believe, regarding the context of this thread, that your questions are misframed. I believe, regarding the context of this thread, that if God did indeed create the Earth, that he created the laws that govern it, which can be studied, learned and testified to, daily, in mathematical experimentation concerning the matter and energy of our world.
I believe that to ask such questions as yours precludes only one answer to this thread: none of it matters because God could have made the Earth in whatever way it seems to look today.
However, that answer ignores many factors, not only the varying interpretations of Hebrew scripts pertaining to creation, interpretations which genuinely allow for the theories of evolution and the old Earth, but also ignores the complexity and testable nature of the scientific theories upon which the consensus of the Earth's age is based. It shows unrelenting bias towards one interpretation of a text written many years after Moses' death, but more than anything it shows an unwillingness to look at other valid theories for the sake of one you find easy to digest.