User blog comment:ShockMainspacer39/Interesting Theory/@comment-4749365-20131129120855

They have been aging though. Chris said they were sixteen in TDI. TDA takes place immediately after TDI meaning they didn't age but maybe one or two did over the two seasons. As one year has passed, all of them turned seventeen with Cody turning eighteen during the season. I don't remember any time span from WT to RotI but the new cast are all sixteen. AS takes place one year after RotI so the new cast are seventeen while the old cast are at least nineteen.