I think that investing in everything is risky especially bitcoin. Dont take anyones advice about what will happen with the currency. Personally I believe we are just starting, just my own opinion and you shouldnt consider that as investment advice as well.
I think Never invest more than you are able to lose Bitcoin is a very risky investment and you should keep in that in mind at all times. especially the price Bitcoin is still going down this time.
I know that there was a plunge last month of January which made some investors to blame their selves and regret in the end. Disappointed is what will other feel if they end up of an empty wallet just because of holding and investing on bitcoin. If you still have faith that bitcoin will increase this year 2018 and the falling of price is just a challenge for bitcoin to make its economy healthier then I think that you can still invest on bitcoin. Investing on bitcoin is very profitable.