If you are like me and have already paid for it in full but are picking it up, call BB customer service once you have it (and while still in the store just to be safe) and ask to talk to a Post Purchase rep. They should be able to help you out
I know the deed is done already, but you ar aware that you can transfer the entire systme from one 3DS to another right? You would have saved you eShop money and your downloaded games.