For someone who is interested in snakes and does not have any experience with them I'd think that a corn or a king would be great! Corns in my opinion are just a great snake that's relatively easy to take care of. Kings, while they can be a bit more high-strung sometimes, are just as easy and IMO are just beautiful (I'm quite partial to my purple albinos lol).

Just make sure she does her own research and understands what whatever type of snake she decides to get requires as far as husbandry goes.