From whence I started was a heathen. Which has nothing to do with with the authority of the Bible. It (the Bible) was the authority before I ever whenced! Or before you whenced. Your laundry list of things to appeal to cannot authenticate in this instance. How would a whencer authenticate the authentic with a non authentic. Or if a whencer has the authoritative document, with what would one authorize the authority with, other than the most authoritative. A whencer wouldn't whence with a lesser authority, to authorize the more authoritative! Hence a whencer whences with the most whenceable. In this whenceality, the Bible.
And oh by the way, your belief, "God doesn't exist", is self defeating!