I actually bought some Bitcoin in the 3rd quarter of that year (2017) and to tell you guys, I'm still in big regrets why I'd never sell it when the price reaches its peak. It was a big mistake but it never gives me losses by then since I sold it early 2018 and the price still in good but it actually most daring if I could sell it when the price is $19k ( it supposed to make it triple from my buying price).
But anyway, it passed already and we'll have to move on and face what is the coming. I know it will be fine in the year and onwards.
Following the same philosophy you might have sold it at $10000 so good for you;) You never try to catch the top. It is very personal and feeling based and usually wrong.. it's better to wait for the top and sell a little after. That way you are not the one selling for 20k, but you are for sure selling at 16k+ and super duper sure you are not the one selling for 10k or even 2k thinking it is the top..