As someone who has been in this since November, I'm sorry to say that the right time to buy was like two years ago. Unfortunately.
the history can still repeat itself with help of volatility, therfor all you need to do for now is wait. besides , the price of cryptos right now had also been droped a major percentage ever since we begin the year 2018 . so i guess buying a crypto these days are still a good idea because their values are still cheaper when compared to their value least year .
i do also believe that there isnt a right time or right date to buy a crypto because the valaue can alaways fluctuate or change from time to time.