User blog comment:Thailog/Ep. 121 "Image" discussion/@comment-4789909-20120318155953/@comment-3462923-20120319195130

Just saying, because it's pretty much been a year (I believe) since Robin, Aqualad, and KF "left" Cadmus with Superboy. And that's still in the same season. So Gar is only 8. Maybe sometime soon in the season season, another year will pass by making him 9. He's probably join at 10 or 11.