Personally, even when I was underage, I wouldn't sell or encourage selling ANY animal to a minor!
Be it snake, lizard, or hamster!
I have seen kids get hamsters, throw them in boxes, with news paper, and some food and a BOWL of water, (hamsters suck at using bowls of water) they would get wet tail or drown and the parents would find out and demand a refund.
Not all teens are capable of properly taking care of the animals. And if they truely want the animal. then they can either wait, or get parental permission.
Plus you are making an oral contract with the minor, and minors are legally not allowed to enter into any kind of contract without parentel permission. (atleast in the U.S)
Neptune, Zion, Enigma,