Bitcoin price trends is upward. It is consistently rising, 2017 is the year for multiple all time high BTC prices and I know it will continue next year.
You can still buy BTC when it fells down a little bit because I don't want to think that it will hit a hard drop. Just feel the market and keep monitoring...
Referring to the current price of bitcoin, it is still an ideal time to purchase bitcoin. Recent price decrease especially since the second week of december 2017 was mainly caused by high volume of sale for taking profit by btc holder. Today , btc price is uptrend since the last 3 weeks. On this condition we are suggested to buy bitcoin and hold it while monitoring future price movement.