Addressing the question at the core of the original post: As I understand it, you are Not bound to the US Navy or to the United States Naval Academy until the start of your 2nd Class (Junior) year when service commitment letters are signed. You don't show up on Iday, you quit during plebe year, you quit during you 3c (sophomore) year, no issues other than the paper work.
I think the only real constraint on you would be your conscious and karma if you accepted your appointment and elected to just not show up on IDay leaving a spot unfilled that others have held as a goal for years.
Sounds like you have some other options on the table still. My DD held her appointment letter for months, weighing other options. She'd laugh about it today her uncertainty today. She's 23 now; has more real friends than any person I know; Her confidence in herself is enviable. She is the leader of a team with responsibly for things that really matter. She received an amazing education surrounded by amazing classmates and the USN paid her while she completed her Masters in Security Studies at G-Town. Right now she's riding around out in the deep blue Pac right now. I don't know exactly where she is but in every note she sends she tells me how much she likes/loves her job. She will be 26 when she completes her service commitment, law school, med school, 3 letter agency's will be options. Ting is she's so happy where she is that I don't see her leaving.------My wife is sooo pissed!
"Dad you know that XYZ event in the news? Yup, that went down on my watch. We saw some shipt that night, but my team kicked ***!"
Chose wisely................... good luck to you whatever you decide.