Thanks so much for the advice. I'm broken hearted right now, but not as upset as I'd be in a year with a monster snake on my hands. If it was any other shop, I'd be hopping mad and spread the word that their employees are full of b.s. As it is, I'll break the news to my son in the morning, with a promise of getting him an appropriate first snake. First thing Monday, I'll go to the shop and talk to the owner, possibly with a copy of this thread in hand. They have a pretty strict return policy on live animals. However, I'm hoping that given our relationship, she'll take it back or give us an appropriate first snake in exchange. I'm pretty sure she will and there will be no harm done to our relationship. OTOH, I've lost a lot of respect for this particular employee, to the point of being furious with him. If he'll feed me a line of b.s., then God knows what he's saying to Joe Shmo off the street. Needless to say, I'm not taking his word on anything other than guppies from hence forth.
Melissa
In tears but eternally greatful for your help.
Edited to add: The Burm is a male. My son just came downstairs and I showed him this thread. He still wants a snake but agreed that taking this one back was the smart thing to do. Time to shop for a truly appropriate first snake.