Investing in bitcoin is a risk, as the value can crash tomorrow.
I'm holding too so far, I believe in what bitcoin represents, so I'm taking the risk. Don't invest more than what you can afford to lose however, but if you can, you should buy more.
Also have a look in other cryptocurrencies.
There is always a risk on any investment so do not bother investing because in cryptocurrency there is always a higher chance for you to earn profit. Bitcoin is very profitable due to high demand on the market and because of that, there are a lot of young wealthy people today who invested early on back in 2013 when bitcoins is just 13$ dollar.