BlackNMild, what makes you think Japan will get it first (Nintendo has not said what region will get it first)? The last two systems, Wii and Nintendo DS, both launched in North America first.
Assuming this rumor is true (I never assume any rumor is true, so I will treat the 3DS release date as the official TBA), why would anybody find it odd? The Wii and DS both launched in mid/late November, the North American release of the GameCube was also in November. The North American release of N64 was in September. Nintendo has a history of fall releases for systems.