you think this is the right time to buy and hold bitcoins? because from 19k its 11k today.

No one knows the honest answer. But sure. Buy in.
It has the potential to go up. Nut it also has just as much potential to go down.
Also look into some ALTcoins.
Marketcap today has gone bloody red for quite sometime now and me myself has been trying to understnd what was happening in the blockchain. Do i still have to continue to hope? I have been trying to find the answer all the questions that has been running through my mind lately. Though i got few answers to myself now, partly yes that it is time now to buy more and keep holding.
