The best snake to begin with is the one you really want to have. The most important thought to consider is how big it will grow and whether or not you can accomodate it and afford to feed it. But to bring a snake into a house where someone isn't sure about snakes make sure you begin with a baby, even if you have to wait a bit. All babies are snappy but their strike will scare you more than their bite. They can't hurt you and are the best first experience to begin with. And the thought of a 10 foot carpet python won't even pass your thoughts while you have a baby wrapped around your fingers

You won't really notice it growing until you put a tape measure to it.
Some snakes are considered to be more bitey than others but could their reputation be coming from ppl who only handle their snakes when they need to, or it could be true. But you still need to be happy with what you get is what you wanted.
I have Port Macquarie Carpet pythons. They are beautiful natured. Gentle and not afraid when I pick them up. But I handle mine all the time. I also have an olive python who is also a gentle giant but has a spirited nature and olives grow to about 4metres (and the rest some believe).
Enjoy a carpet python grow from this to that