[quote=Krayzikk]
Well, actually, judging by that list, there were likely two graduating classes. Well, three counting Orion, because his bio states he graduated a year ago.So there are three seventeen year olds, one sixteen year old, and two eighteen year olds. Sounds like there were likely two graduating classes. Either that or some people skipped ahead or stayed behind. XD
[/quote]

Not necessarily. Based on Yang, Weiss, and Blake's ages at the start of the series (all 17), the freshman year at Beacon would usually be either 16-17 or 17-18. The teams they formed were supposed to last for 4 years, so I'd guess their education at Beacon supposed to last the same duration; taking them either from 16-20 or 17-21, either of which sounds reasonable. My main point is that if all the posted students are freshmen, then the outliers are Orion (who took a year off), Arara (who advanced a year early), Addica and Tirren (neither of whom have any special placement mentioned in their Bios). Based on the information from the show and the spread of ages, I think it'd make most sense and be easiest if the freshman year is 17-18.