I agree with RAWE, try to give your parents the ammunition from the publications that, at least a couple of times, the WTBTS has said that higher education can be beneficial and is UP TO FAMILIES TO DECIDE! If you can reason with them in this manner along with letting them know that this is what you have decided perhaps they will be more open to accepting the fact that you plan on going. That being said I wouldn't really go into detail on the subjects you are taking unless they are ones that your parents wouldn't really find fault with. If you can get them to understand and accept this fact then the door is left open for you when you want to come back to visit or (heaven forbid ) you need help.

Be careful and safe in your new home and as Peanut said check out your new digs before committing if possible.