Not exactly, but you're almost on the right track. Each character can only be a member of 2 societies at a time. One of these is the wholesale society that you have already joined. The other (for provisioners), is the craftsmen's society in your village. This is where you will buy all your books from level 20 on and is home to provisioners, woodworkers and carpenters.
You will only be able to join after you have declared your intention to become a provisioner, (at around lvl 19), and after you have dinged 20 and are actually listed as a provie.
The other 2 guilds, (for scholars and outfitters) will not let you join them so don't worry about joining the "wrong" society.
The location of all 4 societies should show up on your in-game map, (M key), when you are in your home village.