Today, I got the Yearling badge.
I don't remember how my account was created, but I didn't use it for anything until February 2013 when I started being an active user. While I'm not happy with this achievement (because I think that that being logged in for searching answers, and suddenly decide to contribute and gain +200 in a few days should not qualify as "Yearling" beahavior), it seems that the rules for granting Yearling are by-design (see: I got Yearling badge in 273 days, Yearling badge too early, Details on how the Yearling badge works).
In short: I was not active for a year, yet I'm yearling, and that seems to be by-design.
Therefore, the description of Yearling is misleading:
Active member for a year, earning at least 200 reputation
It should read:
Member for a year, earning at least 200 reputation
Active member in a year, earning at least 200 reputation