Most dorms do not allow pets. Most people stay in dorms because it's more affordable than other housing options, and more practical to students who don't have a means of transportation, plus many dorms come with meal plans, utilities, and other benefits. Some schools even require you to stay in dorms as a freshman, or to participate in specific programs or keep certain scholarships. Also, many scholarships only cover four years of school, so working multiple jobs to live on your own with a demanding university degree is not practical if you want to finish your degree in enough time to graduate before then.

I'm not saying that your parents should expect to take care of your snake, but as a freshman in high school you don't know what life is going to bring. And you will need to prepare the unexpected, and consider all your options, for the animal's sake. Some people are fortunate to follow the path that they planned. Others, like myself, were presented with opportunities they never even imagined would come their way. And you don't want a commitment you made at 15 cause you to pass on those opportunities. No one can assume they will be able to live on their own and pay their way through school at 15, and that's why I think any 15 year old getting any animal needs discuss what they will do in the event that plans do change.