No one can tell accurately if it's going to duplicate its success, this is the only year in Bitcoin's 9 year existence that the price did not go up better than the previous year, but it's still profitable to invest in Bitcoin, because Bitcoin is still making a lot of news world wide.
It may, it may not, we will never know for sure until it happens. There is literally no one in the whole world that can properly judge what bitcoin will do in an hour let alone until the end of this year. Hence no matter what people have said here either the ones that said it will or the ones who said it won't doesn't know anything about it and just making up things.
There are professional traders in stock markets who lose money all the time, finance is not something you always come out on top, it is just not built that way. You sometimes win and you sometimes lose but in the end you hope your wins are more than your losses.