Shit man, the stunts I pulled before (and after) joining the military makes your situation look like Miss Goody 2 Shoes. And I'm doing just fine in the pipeline.
I got the living shit beat out of me growing up. When I got old and mature enough and got my stuff together, I ran my ass off, and I have not stopped running yet. It worked well for me in the military. I was able to harness inner rage that enabled me to overcome small stature, and initial physical weakness. My inner rage made my will strong, and as I got physically stronger, my will got stronger, and the various rites of passage that I transitioned helped me harness my innate, pure meanness.
The military is the shit, for me. It taught me to harness these aspects of myself, and to unleash them on command, and then to stand-down when ordered. It's even more important as a commissioned officer, where you are a leader and mentor of sailors and enlisted men. I doubt that I would have had the stones to do the stuff I have done had I not started out as a pissed-off dude.
How it works for you....again, it's up to you. You can change your life. Or you can let yourself fuck everything up for yourself.
Regardless, maintain a positive outlook, impress all that you encounter positively, be calm, quiet, and centered. You will be tested by bureaucrats, sea-lawyers, and professional douchebags and they will tell you that you can't do this, or that, and they will tell you these things in a way that suggests that you are asking for actual skin off their own backs.
Just be cool. You can get there. Best of luck to you.