Hi Juliette! This looks like a baby boy or girl line, because of the yellow lettering. On the back of the tag is a season code, like 11GY BTS1 or 10GY FALL2. That will help you identify which season to look in, and what year it was released. If it is 11GY, then it is a 2011 line.
And just like PP (previous poster) said, there should be an ID number on the back of the tag, too, that you can look up. Be sure to use the code that begins with 140...
So very sorry for the delay in replying! I have to learn how to set up notifications for all new posts!!! So happy you asked, though!