Some retailers have Fire Emblem: Awakening in stock today, which is technically the game’s release date. Others, however, may not have stock available until later in the week.
A few retailers have indicated that Awakening is seeing shipping issues/delays/errors. Nintendo’s response to the situation is that sellers “receive their shipments on different days” due to “the variables of shipping”:
“Nintendo makes every effort to make sure its games and systems are available at retail stores nationwide on launch day. Sometimes, because of the variables of shipping, different retailers receive their shipments on different days. Fire Emblem Awakening can be purchased right now from the Nintendo eShop for Nintendo 3DS.”