Millionaires invested in bitcoin from 2014 and on. Billionaires started investing since the start of 2017 and are still holding.
It must be the best ever decision they have made because from 2014 till now bitcoin price must be changed and it is great at this time. If they must invested at perfect time at that time bitcoin price was not very high and it will grow more till 2018. I invest right now and will wait for more people to invest and get bright future with bitcoin; if I am not billionaires right now then in future I will be millionaires and will invest more to become trilloinres.