I believe that it is not a good thing to sell everything at once because there is a possibility that you will regret it. There is a chance that the price still goes up after you sold everything so you lose money there.
Indeed, I think a lot of people if they sold it right now will regret it later because the profit will now be not much compared with the future.
Most likely you could make a lot more profits in a couple months because of the halving.