Now every one wants to buy Bitcoin definitely it will drop to some extent, so that more accumulation will start.
It's common nowadays that people buy bitcoin because of upward traction to the market which is not that wise because the profit you can get is not that big compared to when you bought it on the days that bitcoin is quiet and you might get into the time of price correction.
Of course the best time to sell is the price for you is desirable, if you are happy with the amount you are having then that could be the good price to sell, bitcoin is very volatile, in a blink you can be rich but in a blink it can make you poor as well. better to have a full focus on trading the coin you want for you not to sell it in lower than the average price or to that undesirable price. Keep in mind that if you have your gain already better to think if you want to make tp or still wait for pump. you decide.