Well, I guess I get to post a dissenting opinion so I will don my flame proof suit.
You are 17--you are a minor. Your parents are 100% responsible for your care and well being until you are 18. They are also responsible for making sure you attend school--in some districts parents can be put in jail if their child has unexcused absences. You live under their roof, and they take care of you financially--you live with their rules. If they tell you you can't go, then the mature thing to do is to respect their decision and wait until you are 18 AND living on your own, AND completely supporting yourself to do things they don't agree with. Unless you turn 17 today, that is less than a year to wait. Learning to delay gratification is a sign of responsibility and maturity. Disney will still be there--not sure if the girl will, but another one will come along.
I won't even go into the moral aspects of a 3 night hotel stay with a member of the opposite sex and the possible future complications of that. Yes, it seems fun and cute now to play "grown up" and get a hotel and go on a vacation and all that, but you aren't grown up. And when you do grow up you will find out that you can't just "skip" work (right now school is your work) for a few days because you REALLY want to go and have fun instead of living up to your responsibilities as a man. Perhaps your parents are trying to teach you this valuable lesson.
As a parent I would be really angry to find out that total strangers are encouraging my minor child to disobey my household rules. In fact, in my home, it would result in loss of all computer privileges for that child at the very least.
Cancel your plans, stay in school and after you graduate go to college or get a job. Go to Disney with your family (current or future) or after you are completely self sufficient. I waited 33 years for my first trip to WDW (and whined and cried and schemed for years before that to try to get to go). Sharing my "first time" with my husband and 2 children was WAY more gratifying than a "quickie" trip with just anybody would have been. And it sounds likely you have been before so it isn't your "first time". You can wait.
That is the sign of a true man worthy of his parents trust and respect.