We were just at SUNY Maritime open house this weekend. I would echo bruno's advice and suggest strongly that you look at the maritime school programs if you really want a Coast Guard career. That Coast Guard third mate's license will open a lot of doors for you, and if really want it you can earn it at SUNY Maritime and (with a little extra work) still major in marine environmental science, if that's your thing. The MMR program sounds like a good deal, too.
I should add that, at SUNY Maritime and, I suspect, at the other maritime college, those who are pursuing the third mate's license (deck or engine) must be a part of the regiment of cadets (as opposed to a civilian student). While the regiment is somewhat less strict than at the SMCs -- for instance, at SUNY even freshmen have liberty every weekend -- you will still have a seperate education through the regiment in military organization and bearing.