Actually the best time to buy bitcoin was a few weeks ago when it dropped lower than $60,000. But it's still a good time to buy bitcoin now before it goes and reach a new ath. Just try to accumulate as much before it creates a new ath.
I don’t think there is a specific time to invest in bitcoin. Even if bitcoin creates a new all time high, I can decide to invest in it as long as I will be investing for a long time, I don’t have any problem with that. The only people who are disturbed about when to invest in bitcoin are short term investors or traders. If you are investing for a long time, just do your analysis and choose when to invest. I know it’s better to buy when the price is still cheap, but some people might not be financially well when bitcoin was still cheap, and they can only invest now.
We all should know that everything doesn’t just end after an all time high or a bull run. Lots of people who sold their bitcoin a few years ago after hitting a new all time high will be regretting it now because bitcoin keeps on growing, and they would have made massive profits if they hadn’t sold then. So after creating a new all time high, later in the future we should be expecting another all time high.