The right time to invest in BTC is seven years ago.
The second best time is now. Although it's probably wise to diversify your holdings among several cryptocurrencies. I firmly believe cryptos are the future of money, but whether BTC or another currency takes the crown is not entirely for sure.
Yes, seven years ago...
I think Roger was absolutely correct in that doco when he said it's never too late to get in and start enjoying yourself and get into Bitcoin. I would caution against buying in at near record highs, but if you're long on BTC and don't mind being patient, there is at least the chance that if you lose in the short term you'll win in the years to come. I find buying in regularly when the price dips is a decent strategy with the lack of financial, economic and whatever information others have.
It seems to me Bitcoin has survived the biggest threats thrown at it so far, and cryptographic currencies generally but especially Bitcoin are not going away, and will continue to have value, even if there ends up a split and/or a successor to Bitcoin in the years to come.