You are on Earthen Ring, at least the character you are posting on. It is connected to Darkmoon Faire realm. These two together constitute one of the smallest English language realms.
However, as Niceoldman said, Blizzard are about to make new Connections, and it is as certain as it can be that Earthen Ring and Datkmoon Faire will be connected with Moonglade / Steamwheedle Cartel / The Sha’tar, roughly tripling the size of your realm. It is also within possibility that these realms will also be connected with Defias Brotherhood, making a really large realm roughly the size of Argent Dawn.
I would hold on for a little bit and see what the connection brings