With the start of 2018 a lof of bad news comes out and it affects bitcoin bigtime, in my point of view it will not reach 30k but it will not goes down lower done 6k too, i think it will be around 11k-16k in december 2018 right now bitcoin is just bouncing back again and i hope it continuously goes up until december.
The prices of Bitcoin had surged up to 18k the last December and the start of this year was a bit down for many investors but the market demand determines the prices of the currency. Besides, the market forces are set to bring the equilibrium in case of disequilibrium in the market. In my opinion, the price will again surge up till the end of the year to 18k or more than that.