FLYMARINES makes a good point that the PLC program might be the best deal for you depending on what you want to do, although it looks like you're pretty gung ho on coming to the Academy. There are a lot of USNA grads who go Navy Air and I don't have the exact numbers of each different commissioning source and what the makeup is for the Navy. You'd have to ask someone who is working for BUPERS. In the Marine Corps, it really doesn't matter which commissioning source you're from. In fact, only about 10% of the officers coming into The Basic School are Academy grads. Almost 60% come into TBS from the PLC or OCC program. So you find out really quickly that you can't be arrogant about being an Academy grad, or become a "ring knocker" as they say in the Navy or Marine Corps for that matter. In any case, there might be a little rivalry, but keep in mind you're fighting for the same team: either the U.S. Navy or the USMC.
Are you going Navy or Marine Corps air? If you're going Navy Air, I can't give you the info about going the route from Navy OCS. I was in a similar spot two years ago: I went to Texas A&M for a year under a Naval ROTC Scholarship and did the whole Corps of Cadets and hated my life because I wasn't at the Academy. Likewise, I wasn't accepted on my first time around, but I made it in on my second try. I was a Physics major (4.0 GPA) and now I'm a Mechanical Engineering major looking to go Marine Air. Of course I'm leaving myself open for criticism, but I came to the Academy to be in a 24/7 military atmosphere which focused on professionalism, leadership, academics, engineering, and athletics. So far, I haven't been disappointed. The only thing that sucks is the liberty policy: you'll only have time to get out on maybe a Saturday or Sunday because of the hardcore academics.
You can do fine with Computer Science because I know many CS majors here. The Academy is what you make out of it, and I'm having a good time with it. By being two years ahead, you can test out of a lot of stuff and possibly start graduate school while you're here at places like Johns Hopkins or the U of Maryland.
FLYMARINES also referred to the fact that you are guaranteed a pilot billet (MOS 7502) from PLC or OCC granted you pass the ASTB, PFT, and you make it through Officer Candidates School at Quantico. If you go Marine Option with an Air contract from the NROTC program, you'll take a specific number of military science courses (i.e. Evolution of Warfare, Weapons Systems, Ethics, Amphibious Warfare, etc.) and you'll do 6 weeks of Marine OCS. If you do PLC: you have no obligation to attend any military classes at your college, but you do have to do two 6-week stints at Marine OCS. For Officer Candidate's Class, you graduate from school and do 10 weeks of OCS and then TBS afterward. After 4 years at the Academy, you have to compete for a Marine spot and then get the Marine Air contract whenever you make your service selection. For the Class of '04: here's a website giving you the details about service selection numbers with relation to Navy Air and Marine Air: <http://www.usna.com/News_Pubs/Publications/Shipmate/2004/03/Career.htm>.
Message me if you want some more information.
