hang onto it
My brother's a yuk at usma, and he got into a couple ROTC programs/the scholarship and USMA. The one thing he's really stressed, though he's happy with his decision, is that a 2LT is a 2LT in the end, and great ones come out of usma and rotc, and bad ones come out of usma and rotc. So definitely, hang onto the scholarship, because either way is a good decision. different, but good
The one thing:
Everything i've read/my brother's had experience with/general reputation is that VMI and the citadel produce the worst officers who have chips on their shoulder from either not getting into usma or trying to play up their individual schools over usma. As a rule, they are tools/dicks/asses, and everything i've ever heard about the subject supports that. So, if you go rotc, go cornell. its a sick school academically, you must not have a problem with small towns (ithaca or utica, i forget which one cornells at) or else you wouldnt consider usma, vmi, or cornell, and cornell and syracuse are the two main/most renowned rotc programs in NY.
so, hang onto the scholarship, consider rotc just as much as you are west point unless you're already dead set, and DEFINITELY go cornell over vmi if thats what it comes down to