It is great that you got in fairly early and did well, however you cannot guarantee anyone that they will double their money. Maybe, yes? Possibly? But not double your money easily. There will be a lot of happy people if it doubles or more.Most people invest when it's too late. Bitcoin has already made its run, quadrupling since its low a year and a half ago. However, the good news is that you can still double your money easily. Get in as soon as you can.
But no one can guarantee that you can easily double your money before the bottom finally falls out.