I believe you need to be a legal immigrant (i.e. greencard holder) to join the military. Even based on the most recent proposal (not sure whether it has passed the congress), you still need to have come to the US before the age of 16.
Honestly, you are much better off finding a local (even if low paying) job than to join the military.
Honestly, you are much better off finding a local (even if low paying) job than to join the military.