I thought you would accept the explanation about FC example, but I guess you dont want to do it for some reason.
It doesnt matter what age FC characters were supposed to have, the thing is the actors "should look" 11 years older compared to FC, and they dont.
You may try to cover it, but it is what it is. Its not realistic.
If you can accept one rule, you should acept the same rule to all cases, but if you dont want to do it in Gambit case, then thats another story, about your prefferences.
Anyway, I tried to explain it, and I did. So theres nothing more I can do, if you dont want to follow the same rules on all cases