I am trying to figure out what I want to do with my life and how to get there. Can anyone help?

I'm a male at age 17 and currently in the DEP for the USMC(I go to boot camp June 1st 2008). I am trying to figure out exactly how I should go about geting my dream job w/o exactly knowing what it is if you know what I mean. I am currently assigned to a MOS of Aviation Mechanics, I picked that at the time cause I am really interested in mechanics and I scored almost as high as possible in the mechanics section of the ASVAB. But now I'm thinking I would rather hold a more important job that not just anybody can get like working in the Pentagon, or for the FBI or something. Is it possible to be both an active duty marine and work with the FBI or in the pentagon or other similar scenerio? How would I go about doing this? Could I go into the USMC active duty then go to an academy and then from the academy to the pentagon while still active duty? The reason I want to go active duty is cause I want to retire from the USMC, not just go in then get out. The reason I want to go into the USMC is because it檚 a challenge, pride to belong, and physical fitness. What would be the best and most likely available MOS to request in the USMC? I am not here to go along for the ride, I am here to make an impact and to be all that I can be.I am trying to figure out what I want to do with my life and how to get there. Can anyone help?
Marine DEP using an Army tag line. Your recruiter would be so proud. You need a 4 year degree to be an FBI agent. You would not be able to do both at the same time. Pentagon duty may come in time. Most just out of advanced training will not be sent there. As far as which MOS to chose, you should pick one that translates to a job in the civilian world. Not much call for a machine gunner or rifleman on the outside..........I am trying to figure out what I want to do with my life and how to get there. Can anyone help?
I like your ambition it sounds to me like you know what you want to do so go for it
You need to try and change anything you need to right now before you get in once in it is hard to change things around you actually have to get permission its not impossible just hard.