It's very risky because bitcoin is very volatile. You should just invest the money you can afford to lose because no one knows how the future of bitcoin will turn. What if you turned all your money to bitcoin and its price crashed and there's an emergency where you need your money. You'll have no choice but to withdraw your bitcoin even if the price is low. And if you do that, the money you left in bitcoin will have little chance to grow. You'll end up losing your savings.
All cryptos involved risk and bitcoin is not spared from it. Those fluctuations really affected too much the bitcoin holders. I think its better to spread like for example in Ethereum, Ripple, Dash,XLM, XEM many others in the top list of coin market capital. So that if one or five is down there are others that might be green. The key here is to diversify.