As investor you don't need people opinion on when to buy bitcoin,  when to sell bitcoin and how much money you need to invest in bitcoin.  These are things you need to make decision on your own, as for me if anyone should ask me when is the best time to sell my bitcoin,  I will say when I have hodl enough and make the profit which I want, if I'm satisfied with the profit I have made from my hodling.
As an investor you need to know when to buy bitcoin and when to sell without asking anyone , if this is so hard for you on when to buy and sell bitcoin it means hodling bitcoin will be very difficult for you and when the price of bitcoin is coming down it will be a difficult time for you to make decision for yourself.