I'm still too new to the game to be able to tell. Also, the restrictions on chat tend to make giving one's age rather a pain in the kiester.
I'm in my mid-30's (I keep looking back, and wondering what that terrain object is behind me, then I experience a moment of clarity from the Alzheimers and realize it's
the hill).
I know one of my officers is in her mid-twenties, and I believe my other officer is younger. Aside from that, I don't know the real ages of my guild.
Personally, it doesn't matter. As long as they follow the guild rules (what few we have), and stay reasonably polite, I'm entirely cool with them regardless of their age.
Were I you, I wouldn't worry too much either. Just play well and courteously and you'll have guilds begging for you.