You can't really choose what you want, even with your past experiences. They don't matter to the Corps, because no matter what you know you'll go through the same school as guys that didn't know a thing about mechanics, and the Corps will make sure they are trained. All they'll look for is if you qualify as in ASVAB scores and certain security clearance or if you have U.S. Citizenship or not, and so on.

From my own experience, I thought I could get Fixed-Wing Mechanic which is 6211, but my recruiter could only give me AF contract which consists of 60XX, 61XX, and 62XX, all my buddies in the school I'm in right now came in as AF as well, which is all aviation but varies by many different jobs. After Boot Camp I got assigned as 6111, which is Rotor wing mech. My school would've been AD, for powerplant/engine part of aircraft, but during the first week at the school they told us there are too man AD, so then I got changed over to Airframe Mech. That's where I'm going to school now. Almost done with first week of school hah. And another surprising thing is, I still don't know if I'm going to be working on Fixed-wing or Rotor-wing. There's wish list I filled out, but who knows? That's how the Corps works. It's all in the needs of the Corps.

There are guys that signed up for AF thinking that they'd work on an aircraft but instead are going to be working on the machines that are going to be used for fixing aircraft.

If you wanna make sure you have that job on the contract before you go to Boot Camp, just double check at the MEPS before you ship out, but still remember that there is possibility it might be changed depending on some situation, such as failing school (one of my Avionics buddy got dropped and will be reassigned to some other job.) IF YOU DO GET to the MOS school of the job you want, don't slack off at the school.

I don't know I thought I was gonna write just few words and it ran too long. hah