The second option is long winded and cruel to your parents, but its your perogative. Tell your parents you will give it up, don't give it up, apply the scholarship to your tuition. If the parents make the check out to you, cash it, apply what you need, and put the rest in a savings account. If they make it out to the college instead of you, I would call up the school's billing office and ask how credits are applied if you overpay. Then if they make it out to the college, apply the full check to your school, then let the excess be applied as credit to your next semester or just refunded to you depending on the school policy. Once you join college, regardless of your age (be it 12 or 22), the college is prohibited by federal law from releasing any of your college information to your parents unless you specifcally authorize them to. (your bill/classes/grades ect.) If paying out of state tuition, you should have enough money after a single year to pay room and board for the rest of your college life. If in state, you need to progress to field training before you reach that point. At field training of course, your parents will learn the truth either way.
The parents on this forum will likely disagree with this option as adamently as your parents seem to disagree with you wanting to complete AFROTC, and i I certainly understand it. Just remember that you want to become an officer, you CAN, it's not something your parents can stop.