While I personally never liked the Marines, I won't tell you that you would make a bad one. But the point is that, as a person who does not trust easily, you ought to know better than to want to trust the World Government in any capacity. Much as it pains me to admit, both the Commodore and the Vice Admiral are men of honor who would not hurt you or use you and discard you, but entering the military is a gamble; you never know who you'll end up with. Are you sure you know what you would be fighting for?