I guess Bitcoin will cross $25K by the end of January 2018.
Hell, at this rate we may even see $25K before the end of 2017. But even if we don't, I'd say we will definitely be past the $25K mark in January 2018, because it looks like the price will continue to rise.
Definitely 25k will increase up to 30k before the end of 2017. Because there is possibility a fork will come before the year end. It will be a new start for 2018 and the price will be continued increase to 35k-50k in 2018.