Just imagine the price of bitcoin in 2016 and 2017,it was enormous right so you need to wait for your time to come.
Don't forget that, bitcoin price of 2018 January and now, after 9 months of time it went down rapidly and lose more than 2/3 of investment so far. Long term investment is better if you can forget it for more than 2-3 years. Otherwise you will end up with lose of money.