It appears that shipments of Fire Emblem: Awakening have been delayed, as a number of major retailers have indicated that they game is not yet available for purchase.
Amazon notes a "potential shipping delay," while both Best Buy and GameStop have it currently listed as unavailable. According to Game Informer, Best Buy is now expecting to receive the title on February 6th. GameStop is anticipating shipments of the game on the 8th.
If you want to play the game now, you can always just head over to the 3DS eShop and pick up a digital copy.