I think that it will even go to 20k in 2018, because bitcoin has the potential we have seen that it had risen 6k in a year this means that bitcoin can also do this again.
So i think that in 2019 bitcoin will surely have hitted 20k at least.
In one year up to 20k sounds insanely, but taking into account how the price of bitcoin is changing now can not be affirmed with 100% probability, which is impossible