User blog comment:Zathronas/Analysis by an author: Volume 2 episode 3/@comment-1618120-20140808094016/@comment-24218038-20140808124512

Several decades? Let's do the math

Students come at Beacon at 16. Ruby came before that, I would say 14 but let's put it at 15.

Let's say Summer had Ruby at 20, could have had her sooner or later but it seems about right. That would give her 35? 36? (if she weren't dead.)

Not that big of an age gap. 15 years would be enough. Which would make winter 31. (Oh and my own sister and I have a 9 year gap. so 15 is definittely possible)