User blog comment:Robykirby/How old is Nora?/@comment-24342832-20140516065000/@comment-4010415-20140516070907

Somewhere, we got the confirmation that Blake, Yang, and Weiss are 17 and that Ruby is 15. It seems that the academies follow the same rule as schools in our world, where each grade/year is made up of students that are all the same age, but if you are exceptional, you're able to skip a grade or two. This is pretty much inferred by what Ruby said in episode 1: "I still have two years left at Signal, and then I'm going to apply at Beacon."