I'm feeling generous today, so I won't dogpile onto a young man that has so much potential. Scoober's right, you need to want to be a Marine first. HAL and I talked about this, and it's mainly because of the "warrior ethos" or "cult-like-mentality" of the Marine Corps.
I've got an easy way for you to figure out which one you want to be... Ask yourself the following question: "If I get the NAMI-Whammy and I can't fly, what do I want to do?" If ships, subs, or other Navy stuff is your answer, than go Navy. If crawling around in the mud is your answer, than go Marine Corps.
I asked myself that same question over 10 years ago, and I went Marine. I'm glad I did.