Either way, even if the universe is indeed finitely old, this does not prove that the God in the Bible is its creator, nor does it prove that nothing existed before this universe. Nobody really knows anything beyond the Big Bang.
I would be careful with your statement. It is easy to confuse scientific knowledge with the many other types of reason and knowledge that exist. It is safe to say that science provides no answers to question of what existed before the Big Bang. That does not imply that there can be no knoledge at all, just not scientific knowledge.