Musa, they're responding to a thread that hasn't been opened since May 30th. Chances are, the other two they're talking about aren't even paying attention to this thread anymore, so why are they bothering?
@Eevee and Musa; The issue isn't the age, but the relevance of the posts that contribute to the topic. In this case, the poster that necro'd this topic is not really adding to anything and commenting on something long forgotten. On the other hand, Musa's first response to this topic is at least half relevent (yay Musa!). But instead of continuing on topic... You kinda spoilt things by not adding to it Eevee. Just sayin'. ^_^'
I've always put Gakupo as in his prime, about mid-late 20's. Going onto that age where he should be old enough to know better, but still young enough just to be naive.