Julien Berman is a Post Opinions intern.The best investment you can make isn’t in stocks or real estate — it’s enrolling in college. At least, if your family is rich. But for America’s poor, it’s not so simple.On average, workers who complete at least one year of college significantly outearn those with only a high school diploma. This “college-going premium” reflects the relative demand in the labor market for college-educated workers. Most students who enroll in college graduate, and over a li...