Thread:Thunderbird3InternationalRescue/@comment-25600892-20191005234253/@comment-33744259-20191008211307

Yup, specifically around 16-18 years old (human years, that is), and the Cutie Mark Crusaders are kindergarten or elementary (1st Grade most likely) school-age. As for Celestia and Luna, I like to imagine that they're in their late thirties-early forties (again, in human years), and the reason why they're so tall is because I imagine that both went through growth spurts.