As long as you're not buying at a current ATH then I generally think most any time is a good time to invest in BTC.
This month all digital currency prices dropped dramatically, this is because the number of people who buy bitcoin and other currencies so that the exchange rate decreased. The key if you play treding you are patient, because it does not close the possibility of bitcoin will rise many times over the previous price. When bitcoin prices are falling as dramatically as they are today, bitcoin players will sell them for less.
For me, it is the right time to purchase bitcoin because bitcoin price is still increasing, even bitcoin amount is fluctuating too much it is the excellent time to buy. Now bitcoin price is at the rate of 13,000-14,000$ and if you have the resources and money dont hesitate to buy because of bitcoin price increase at 5-8% per week, and you can make a lot of profit on it.