Re: About two-thirds of Vietnam veterans were volunteers, not drafted.
Many commissioned officers were there because of the draft. GWB comes to mind, had he gone there. They would come out of college, deferments over, and face a harsh reality. And the army enlisted about 10 people for every Warrant Officer pilot they needed, simply washing out the other 9 and handing them a rifle.
E-5 in 13 months is absolutely incredible. Congratulations. Takes a good brain, discipline and usually someone interested in you.