It's never too early to join a guild! A guild should be a group of people who like to play together, so you want to get to know each other.
I await the release of MEO (as well as Guild Wars and other games), as part of a guild. If you are looking for a guild to join, which is certainly worth your time, you should check out the MEO forums. They have a whole forum dedicated to kinships, and there are some helpful lists. Though you are right to largely avoid those...
There a good number of dedicated RPers out there who have formed guilds, and none of the guilds have grown very large in size. They shouldn't be large, anyway. I'd say that the guilds you see the least of on MEO forums are most likely your best bet.
Here's a short list of some guilds that might be worth your while, with links to their sites:
Elves of Imladris
Fellowship of Forces - Website currently not found...will check into that!
Iron Guard of Nogrod
Knights of Dol-Amroth
Mithril Knights of Evendim
Order of Shadow
Rangers of Thintaur
Safe Havens of Arda
United Guard
The Dunedain
The Moriquendi
The Craftsmen of the Shire
The Hobbits of the Shire
The UC of Dunland
The Eriador Expiditionary Force
And if you truly are a serious, dedicated RPer... I am a member of the
Soul Assassins, and our guild might be right for you. That is, of course, if you're not
completely set on your character being one of the Eorlingas.
Hope I helped, if you even still wanted it.
-Durelin