Board Thread:Questions and Answers/@comment-15835234-20160810003412/@comment-679780-20161012151553

Myself 123 wrote: Tails has always been 8. They may have retconned that as of Generations, it's hard to say. I believe retconned. In Sonic JAm the profiles in the character museum are the same as Modern characters age and so on. Way Isee it, Classic characters are roughly half the age of Modern characters.

Which makes sense given in AoSTH Tails claimed to be 4½ years old.