There will never be a perfect time to invest, more than likely, unless you're extremely lucky, you will buy and experience both dips and peaks. If you can afford to lose your money invest it, if you cant, don't.
At the moment prices will be lower than they have been due to people cashing in to pay for their Xmas shopping. I would expect that, and this is purely speculation, once the banks reopen, after the Xmas break, prices will probably bounce back up. But, that said, they will probably drop down again for new years/around new years due to people over spending when celebrating the date changing on the calender.
This is absolutely right because No one knows that which time is best to invest and some how it also depends upon your luck regarding good timings.
In my opinion, as bitcoins price has fallen now a days so one should invest in it now because the price of Bitcoin will Bounce back to its peak in 2018.