It’ll only take a few seconds
Do you have a Nintendo Account? There’s no rush, and they don’t appear to do anything just yet, but you can sign up for one right this very second if you’d like.
These accounts will eventually be good for a number of things, including loyalty rewards, and hook into the company’s upcoming mobile apps. Speaking of which, pre-registration for Miitomo is supposed to open tomorrow. Why bother? For points, of course! Gotta stock up.
To expedite the account-creation process, you can log in with an existing Nintendo Network ID (that thing you use to post funky stuff on Miiverse), and most if not all of the fields will be filled out.