I think that this deck will be good in the later game, but I don't think that you should rely too much on Fog to protect you for the first few turns of the game. to me, those turns are crucial. you need to get some creatures out on the battlefield early. I would try a card like Elvish Archdruid to power up your elves in the early game.
check out my new and improved wurm deck: When Elves And Wurms Ally...