<p>I was one who did military first. You do not lose anything mentally; in fact, you gain. Most military veterans do well in college, and most of those will tell you they may not have done well right of high school. Veterans also get a number of advantages if you use the GI Bill and they have a preference for admission to most public universities (state laws mandate it); moreover, most colleges, even if not required to give preference, view a veteran as a highly desirable candidate. Your description of yourself and possible reasons for military easily describes a huge number of people who enlist. And contrary to a suggestion above, the military does not want dumb people. Most of the things the military does today requires putting recruits through training that requires mental acuity and makes freshman year in college look like grammar school.</p>