I suppose that BTC will increase end of this year up to $15000, but there is more possibility to increase it dramatically.
I think bitcoin price is hard to speculate this year. From the start of the this year 2018 bitcoin is consistently low. But I still hope for a good price by the end of the year. No one really knows what is ahead of us this coming year-end. $15,000 is very hard to reach because as of this writing the bitcoin price is playing at $6,500 almost halfway of $15,000.