@Taumantis on Twitter, Shared this image as a reminder of what things looked like on January 1, 2017
There are a lot of coins in the Top 100 that didn't even exist on January 2017. There are coins that have done 2,000% increases in the past 30 days.
There is no way of knowing if the gains from last year will reflect the gains to be had from 2018.
However, there is a good chance, if it isn't a shit coin that disappears, that what ever you are holding on January 1st of 2018, will be much much much higher come December 31st of 2018.