sheperdless, "Surely God could not have always just existed; that makes no sense."
But before matter existed, there existed no time. So "Jesus was with God for countless millions of years" - well, he wasn't because time did not exist before creation. If, of course, a spirit being is void of matter. But imgaining a "time" when time did not exist - gives me headache and makes me grab my daily bottle of wine. If God is outside the Universe, in an "area" where there is no matter - he could not have created during so and so many years, but then he created everything in an instant, whereas the results of that act of creation expanded, lasted, forwards in time.
This evening is going to be long. And heavy.