Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-74.73.18.44-20130723204915/@comment-13965604-20150801135322

Jestermonkey4u wrote: ^I shared the same idea back in S1. As you may guess however, I was made aware that Derek's age is unknown until it's said in the show. :)

and that's true, we can't know for sure. But we can deduce things based on canon events, and make sure that it is known that it is just a logical deduction based on things we have seen. And there's definitely been more since season one that confirms the 22/23 age. Since per the pilot script Derek was supposed to be 19, and the thing with Kate could've been SUPER GROSS but we have since learnt that Derek was in high school for some time before the fire, so he couldn't have been 13 when Kate effed up his life