The Crawling Fear

I saw a snake the other day, and I have been thinking about it ever since. In the 20+ years I have been living in this house, it is only the second snake here that I've ever seen. This was a baby snake--maybe I should say a toddler snake. He was on my patio between me and the pool and I almost walked out barefoot when I saw him about 3 feet from the door. I took a glass of water and splashed it on his tail until he crawled away (he was probably living next door in my neighbor's jungle which he cleaned out the other day for the first time in years). The funny thing is that he did not send a chill down my spine.
I have always been deathly afraid of snakes. I grew up in the country with them. Seeing garter snakes and especially king snakes in our yard was commonplace. But in the roads and around the creek we also saw rattlesnakes and cotton mouths or water mocassins. My fear of snakes has always been so great that I put off taking Biology in college until the last year and took it in summer school because I didn't have to have a lab. Being in the lab meant being in the same room with a snake. I took the other semester of Biology by correspondance course. In high school, I had a friend find the place in the science book with the snake pictures (there were always snake pictures) and had him or her paper clip those pages together so that they wouldn't fall open accidentally and I'd have to look at them. When I was about 12 my brother chased me around my aunt's house with a realistic rubber snake that I knew was rubber, but I still screamed and ran hysterically from him. I shook for hours. I seriously considered at one time going to a psychiatrist for desensitization---that's how bad my fear was.
I hope I don't see the little snake's parents, but I would regret greatly finding him dead in my pool's filter also. I want the little snake to live, and he can live around my house as long as he keeps out of my way. I don't mind knowing that he's there somewhere. I hope he moves away when he is grown.
Now, the mysterious thing here is why do I feel this way? Why don't I want the snake dead (he didn't look like a poisonous kind by the way)? What has made me develop this sense that I don't have to run screaming from him with a cold pit in my stomach?
Another mystery of age?