I would get your parents involved. The GC and administration is far more likely to feel they can push you into backing down on this than your parents. You also have to be fair to other applicants. If you are not interested in your REA school, cut bait and let someone else have the spot. While I understand your desire to have a backup, you’ve got to be prepared to compromise in the negotiation. After all, you must have been aware of this policy when you applied to begin with, and you still pulled the trigger.