Board Thread:General Discussion/@comment-26226441-20170214015517/@comment-26018514-20170214091217

The "Ruby is sixteen" thing is a separate matter entirely from the retcon or the battle of Beacon... We know Ruby is sixteen due to the full changing of the seasons at her mothers gravestone... It has seen winter twice and fall once.

Again, this is not AFTER the battle of Beacon, it is over the entire run of the show, we only see the confirmation that Ruby in "Red" to Ruby after the V3 End credits has seen a year of experience, and thus acknowledged that she is definitively a year older. However the other girls were not introduced that early and have no similar locale we can see seasons change in.