Quest Areas
From Polar Lights Wiki
The columns in this table show the map areas that each race starts in, as well as the nearest areas to continue questing in as you gain the appropriate level.
Worgen, Goblins and Pandaren are unable to leave their respective starting zones until they have completed the quest chains there, and other races are unable to travel to those areas.
The remaining races however can play in any area matching their faction, so if you have a friend who has rolled one of these races, then one of you need only travel to the other's starting area.