If you bought your 3DS before 11th August but were unable to register it in the eShop for whatever reason, you're probably all bummed out that you won't be able to claim your 20 free games starting on 1st September. If you're in Europe however there's light at the end of the tunnel, as Nintendo is offering you another way into the free download plan.
Anyone who created a Friend Code with their 3DS and connected it to the Internet — not necessarily the eShop — at least once before 12th August is eligible for the 20 free games. Even if you haven't connected your console online even once, if you've kept your proof of purchase showing the console was bought before 12th August, you can claim those games too.
Nintendo Europe will soon release an online tool that will allow you to verify your entry into the plan, or enter if you've not been online yet.
As for Nintendo of America, it has confirmed that anyone who updated their 3DS console is automatically registered as an Ambassador, with more information about the scheme due next week.