Only thing I can say is stay in school.
When I was 19 I dropped out of college, then joined the army, was injured (non combat) to be discharged, then spent 12 years working in construction until a catastrophic injury in 08, and disabled since.
My life would have been completely different if I would have stayed in school. I still would have joined the military, I just would have had more options like flying a hilo over driving tanks.
I don't like to talk about my life in a public forum, but I just don't want to see someone make the same mistakes I did.