Where do I start?
Since the Big Bang remains a "theory" and not "Scientific Law", it is just as likely that God created the universe!
We know through historical proof that Christ existed. Christ stated that "I and my Father are one" (John 10:30). What does that mean? Is Christ saying that they are related to each other? Perhaps. Is he saying that both are Divine? Maybe. Or is he saying that they are literally one? Hmmm.
Miracles, that were witnessed by thousands, came after God was asked to intervene, i.e. read the Book of Exodus. Coincidence? Not hardly.
Consider the Great Flood of the Bible. Noah insisted that God instructed him to build an ark (Genesis 6:14-18). People thought Noah was crazy. Then, it started to rain. Recently, the National Geographic channel did a documentary on this subject. And they found dramatic evidence that such a flood did occur. Did it literally consume the entire world? No proof of that, but ... There was plenty of evidence to prove that it consumed the region that those [living at the time] would have known as the world. While the search for remnants of the ark continue, we are left to assume that Noah had communication with God. And that his experience has transcended many ages and religions.
Believers and even non-believers have, in desperate times, called upon God. Their prayers were answered. How do you explain that? A Believer will tell you that God is real & present. Are all prayers answered? Not always. But that involves a different topic: The Will of God.
Last but not least, prove to me that God doesn't exist. What is your basis? You see, I have had a sick child at death's door ... Prayed for a miracle ... And even his doctor's told me they couldn't medically explain his recovery. I've had personally healing through prayer that felt as if my body was on fire. Believers call it "Laying of hands". All I know is that the tests that were made before it happened looked nothing like the tests that were taken afterward. It too left doctors scratching their heads ... The mass was gone. You want proof ... Be careful what you wish for. Thomas also wanted proof and it was provided (John 20:24-29). Believers KNOW that God exists, because they have had the opportunity to see Him work. They DON'T need anything else!