I am not sure of your age, but you seem to be college eligible. There are a number of options available to you that can combine a college education and military service. In all of them you graduate with a four year degree and a commision in either the USN, the USNR, or the USCG as an Ensign.
The first is the NROTC program, available at many colleges. In addition to your normal classes you will take Naval science classes as well as training during the school year and summers. You graduate as an Ensign in the Naval Reserve with the option of going active duty.
The second is receiving a congressional nomination, and then appointment, to either the USCG Academy at New London, or the USN Academy at Annapolis. In either case you will graduate with a four year degree and be commisioned as an Ensign on active duty in either service, or, in the case of the USNA, the option of the USMC. There is a five year service commitment. The service commitment becomes effective day one of your junior year, if you quit or flunk out, you'll be chipping rust on some ship somewhere for five years.
The last, and the one I am most familiar with, is the US Merchant Marine Academy at Kings Point, New York. In terms of degrees this school is, at once the most limited and yet the most expansive. You have a choice of two degrees; Nautical Science or Marine Engineering. There is a "dual" program which allows you a double major, but it is extremely difficult. The majors have had their titles changed of recent but basically remain much the same; you will be trained as either a deck officer or an engineering officer upon merchant ships, graduating with a bachelor's degree, a license as either Third Mate-Oceans, or Third Engineer-Unlimited, and a commision in the USNR. None of the other options above will earn you the USCG license, not even the USCG Academy. And Kings Point is perhaps the most difficult of the schools to graduate from. The reason for that is that you take four years of college courses in three years. Six months of your second and third years each is spent as a midshipman-cadet on board merchant ships travelling the world. You are, in essence, a junior mate or engineer. Summers consist of a week or two off, if that. I say the education is limited in that there are only two real majors to choose between. It is more expansive in that you preserve your options of going into the military, be it the USCG, USN, USA, or the USMC. I have a couple of classmates who just made Admiral, USN. You also, as many do, can go to sea on your license, progressively raising it towards either Master or Chief Engineer. There are also a huge number of shoreside jobs available under both majors, with more initially in engineering. Around 90% of steamship company presidents and vice-presidents are Kings Point grads. If you want a career at sea, this is it. In the Navy, CG, and so forth, you spend more time ashore than at sea. Merchant Marine officers spend their entire careers at sea, unless choosing to come ashore at some point.
I should explain the inherent difference between a merchant officer and a naval officer. On a merchant ship, crewed by 19-25 men, the expertise and it's exercise reside in the officers. In the Navy it resides amoung the senior enlisted men on ships carrying crew of 200 to 3000. On a Navy ship there is a quartermaster shooting stars or an engineers mate fixing a feed water
pump. On a merchant ship an officer is doing these duties. Naval officers are more managers, merchant officers are more hands on. At the other federal academies you can major in Russian studies if you wish; at Kings Point it's deck, engine, or dual. There is no commitment, until graduation, of service as at the other schools. You can flunk out or quit at any point.
I said this is the most difficult to graduate from because of the work load. You will start with seventeen credits per quarter to help you acclimate to the environment, then you'll be bumped up to twenty and over. Fall below a 2.0 GPA and you're gone. Less than one third of appointments make it the four years, and there are far fewer appointments than at the other academies, about 350 per class year.
In my opinion, the most expansive opportunity is attendence at a four year school with NROTC. You can major in what you will, the commitment to the USNR is five years, I believe, you can go active duty upon graduation and then into the reserves , or you can pursue a career while remaining in the reserves. Of course, there is always the chance of being called to active duty whenever you are in the reserves.
In my opinion, the down-side to being an officer in the Navy or USCG is that you are much more likely to be spending time sailing a desk than at sea. The enlisted men in both services, IMHO, get to have all the fun. So, if you want sea duty, bear that in mind.
I hope I've answered some of your questions.