Why do you believe the earth and universe are old?
The Bible speaks about previous ages of the earth. Even in the Genesis account, when properly translated, language is used that states the Earth had become a "waste" and a "ruin" and was not created at that time.
We have located artifacts on Mars that where obviously built by beings that had the same kabbalistic belief system that the power-brokers do today. These ruins are very old. It is also becoming apparent that at least one of the moons of Saturn has geometric structure that defies natural processes (sound familiar

).
These and other legitimate scientific positions indicate an old universe, and the Bible is in complete agreement with that.
How old do you think they are?
I don't know. I think that science has a hard time with that question, as I have heard several honest and qualified physicists admit.
Was there life before the recent preparation by God?
Yes. The angels existed before the re-creation of Earth, as indicated by the fact that they shouted for joy during the event.
I also think the discoveries by Hoagland are indicators that the fallen angels have been here for a long time developing technologies that allow them to "walk among the stones of fire" as the Bible puts it.
The stones of fire may be the planets and the fire may be the sun. This simplistic language may have been used so it would be digestible (even if not completely understood) throughout time.