im afraid its time for the honesty train to come rollin through.
if you are goin in the marines one day, then gonna be a day-trader the next, then finally decide to go to community college, you need to seriously review these white-collar aspirations of yours. theres only so many good-paying jobs in a sector like that, and think of how many millions of kids are smarter than you. they were smarter in high school, then went on to a better college, and they're always gonna be better than you at economics because they were into it from day 1.
you are grasping for straws here. why dont you pick a skill, like electrics or plumbing, start learning the craft and the business, and make peace with the fact that it is your destiny. it will save you money and disappointment.