No one can tell you when it is the best time to buy bitcoin that is a personal choice that will depend on who you are as a person and as an investor, if you are willing to hold your coins for years them buying bitcoin at the current price is a good idea, but if you are not willing to hold your coins if we begin to see a negative trend in the price of bitcoin then it could be a good idea to wait a little bit and see if this is just a minor correction or if this becomes a crash.