I took the Armed Services Vocational Aptitude Battery (ASVAB), and scored really high, which is something to consider because grades in high school were B average.
The recruiter was all excited and had with him a large binder full of every job available in the Army. He asked me what my interest was and as I started to leaf through the pages he asked me when I wanted to leave.
My response, why next week of course. He promptly took the book away and left the room. He came back with one sheet of paper and three jobs to choose from because I was set on leaving so soon.
Option1 - Parachute rigger
Option 2 - Tank mechanic
Option 3 - Bradley Fighting Mechanic
I did not want to jump out of planes, and the idea of a fighting mechanic (and the recruiter did not say anything to correct my miss-perception) sounded interesting, so that is what I became. Now a lot of people talk about the horrors of basic training, but my experience was completely different.
The best advice I ever got regarding basic training was to not be the best, not be the worst, and by all means do not let the drill sergeant know your name.
So that is what I did. I worked my tail off, learned how to create structure for myself, and thrived in the environment.