You are only 13, a life is a heavy responsibility, not one you can end because you/your family cannot afford it. Do a lot of research, save up a lot of money for emergencies/vet bills, then think about getting more. Trust me - I have a rescue RTB that no one got treated, she has cost me almost $500 in vet bills over the past year and she is just now starting to get better. If a snake is left untreated for illness/injuries it will be that much harder to fix it later, so the sooner you figure out if you can handle what ever problem it has the better, because if you can't you can find someone sooner who will be able to.
This guy speaks the truth. The wife and I have money put away for every one of our pets just in case something should happen.