Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-72.192.213.236-20130731063426/@comment-1587802-20130802230656

His older sister, Laura, was still in school when the fire happened. That means that his sister was either a junior or a senior. If she's a senior, then she was 17, Derek was 15, and now Derek is 21. If she was a junior, it could have been the year of the Derek/Paige story, when she was 16, Derek 15, making Derek 21 now, OR, it could have been the following year, when she was 17/a senior, Derek 16/a junior, making Derek 22 now. So Derek is either 21 or 22 now.