I agree with the above poster on the bhb idea. I have a baby ball python from them, and had a pleasant experience, and will order from them again.

If you mom is against it, maybe get her to read some things about why petsmart snakes arent the way to go. I am a newbie to reptiles, but I can tell you what I have read in terms of what to look for, health wise.

Check for mites, stuck shed, make sure the belly is clean, no brown/copper discoloration. Make sure his mouth is clear, and is not open and wheezing. Ask the pet store worker to do a feeding so you can see if it will accept food.

That is all I can think of now, but I am sure more experienced persons will chime in with other ideas.

If I were you, I would seriously try to get your mother to steer away from petstore snakes. You will feel much better having one that you KNOW is in top shape to be your pet