The Ambassador program, a 3DS initiative by Nintendo promising free games if you bought the system in its first few months, is just around the corner, so it's no wonder people are worried about the lack of reassurance on eShop or not having received a confirmation notice for their free goodies. Nintendo seems to have noticed, for they've produced a simple way to check your status online. To check on where you stand, head over to the company's confirmation page, input the serial number located on the back of your 3DS, and voila!
With that said, it seems some have encountered problems when using the tool. The company insists you must include the boxed digit at the end of the serial number, but if it doesn't confirm try re-entering the number without it. If you have any other trouble and you can't even access the eShop from your device, you can reach Nintendo at 1-800-255-3700 and go from there.