How legit is the Bible? (by the way, quoting the Bible as evidence to its validity is circular logic.)?

It's obvious to me that there is some sort of creator god, or at the very least, intelligent design. Spending five seconds thinking about the intricacy of my circulatory system makes that very clear to me. It also seems logical to me that this "god" could look at his disappointing creation first with regret and anger, and eventually compion, even so far as to roam among them and show them the path to their true destiny, his original plan for them. The Christian stories of God and Jesus make sense to me. What doesn't make sense is much of the book of Genesis, which was written by Moses. How would Moses know how exactly God created the Earth, or how long it took him? Why does nobody even seem to mind that there is a talking snake roaming around? If I ever encountered a talking snake, I would most likely lose control of my bowels and seek therapy. The last thing I would do is take dietary advice from it! Am I less of a Christian if I don't believe every word of the Bible?