I sold almost all altcoins and always do so with a large growth of the BTC. It's never too late to buy it back.
In my opinion it's an inappropriate action, even though the bulls are happening, not only bitcoin who experience price increases right? even a lot of altcoins also experience the same effect, even the price changes can be much higher than bitcoin. Moreover diversify not only give you big profits, but reduces risk also, I won't use all my capital and be centered on bitcoin, I will definitely divide it to another altcoin