Just opened the game for the first time, very excited, but I'm become suddenly nervous at the first decision of the game. World Selection. I'm nervous because it says you cannot change Worlds, (unless you pay a fee) which scares me. I'd rather not make my first decision a very bad one, and select a world notoriously filled with jerks, or a too quiet/too busy world. I'd generally like some help explaining this as well please, because it surprises me that they confine you to one world for your entire gaming experience, no chance to meet new players and interact with real world friends who may be on a different server/world.
Your world selection isn't really that permanent of a decision. You can "guest" on any server you wish to (which basically is the same thing as playing on it), only your WvW server is really determined by your home world.
That said, you can change your world at any time for a gem fee. Gems can be bought with real cash or ingame currency.
Monster Hunter 3 Ultimate Coming March 19 to Nintendo 3DS and Nintendo Wii U, demo coming February 22