Should I invest into Bitcoin now ?

In every time people say that now this thing is costly example in 2012-13 Bitcoin price near to $100 to $ 150 that time people say its very costly now in 2018 price near to $ 10000 at this time people also say its very costly but now $100 looking very cheep price of Bitcoin so dear friends don't think the today price of BTC. The price of BTC increase more than 50% in a year if we invest in this time it will be near $20000 in end of the year or 2019 mid so don't think as much. Start from a small amount after that when you have believe on it you can go for big.