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.
Truth it is risky but it is about how you take the risk and handle everytime the value crashed also if you want to hold longer always think the positive way and believe that it will give you more profit. I also hold my btc until now because i strongly believe that it will give me more money soon.