Yes $4K is the perfect time to buy bitcoin. The problem is when, we don't know it happens. I think it's a loss have to wait while we want to invest in bitcoin.
Now the price goes down, so maybe we'll soon see a good price again for the purchase. But, I would not like to see how my capital decreases. So I want the price to go up
Although you want the price of Bitcoin raise more and others also want that, but if the whales do not want the price of Bitcoin raise, you can not change the fact. However, you are lucky, the price of Bitcoin has bounce again to $5,500 after dumped near $5,000 price.