I might also point out that freshman admissions tend to average 18 years of age for both sexes. In other words, those "Frat Boys" are old enough to be service members and some of them are. Those are men. Young men, but men.
I get what you mean about calling them “boys.” I was in the Navy at 18. My shipmates and I had real responsibilities and gained experience no college could provide. OTOH we were goofballs. We need a word for “almost men.”
Sorry, that’s “it would take two years at a four-year institution”. I blame the FR proofreader. Or Society.