I'm going to guess that Origins is having distribution issues like some other 3DS games out there right now (Zero Escape, Professor Layton, etc.).
I checked Canadian Amazon, it says they have it in stock, but it will take five to eight weeks to ship it, and when it's that long, that usually means they have to get it right from the publisher, rather than the distributor, and they don't have any in their warehouse. Don't know if it's the same for American Amazon, however.
Alternatively, you could check other sources, you know?
EDIT: Just checked Amazon.com, Jimny is right. You can definitely order it, and they are offering same-day shipping, etc.