We tend to only chime in if we think we have something of substance to add.
You posted this in the Articles section of the ISTJ forum.
As for my thoughts on your question, no type of military or law enforcement career has ever sounded particularly interesting to me. Contrary to stereotype, working within strict authoritative structures has never appealed to me in any way. It's probably not what you meant in your question, but the only area that would probably appeal to me would be as some type of forensics investigator.
Forensics investigator sounds good to me too. Other than that, I don't think any branches of those organizations you listed would be too bad for an ISTJ, going by cognitive preferences. Personal preferences beyond type cognition however are also another bunch of factors you want to consider when choosing a career. Good luck.
I met a psychology professor who teaches at a local college. He told me that he thought every military Non-Commisioned Officer he ever encountered was an ISTJ. If you are not familiar with the term, those are leadership positions similar to foremen in the workplace.
Most of my life was spent in the military and the U.S. federal workforce doing the type of work you seem interested in. In short, there is no one size fits all. Before you head down that path you should do your homework. There are many potential employers with vastly different missions. Yes, personality is important, but do the work (mission) you like. If you do that, work will be a lot less work.
Best of luck. By the way, go to college and get a degree. Being degreed is not the be all end all, but it is an excellent door opener to jobs that pay a lot of money.