First, don't invest all your lifesavings, leave something just in case. In fact, if I were at your place I would invest at max half of this sum and the other half I wouldn't touch.
You can choose some prosperous altcoin, like ethereum and you can risk with some shares but for that consult some broker first.
Ethereum can be a good choice just like what the saying is, don't put all your eggs in one basket. But it's also good if you want to hold 5 bitcoins for long term. And invest into reputable casino's to their bankroll's, actually there's a lot of good place to invest your bitcoin you only need to look for legitimacy.
actually there are many good places to invest bitcoin 20 BTC you just need to find the best, in my opinion better 15 BTC will I take my money being withdrawn and then I put a bank that you think are trustworthy and safe for long term or deposit for future use as a guarantee of the old days to live old age guaranteed and my kids for the future. the rest of the at that I keep in my bitcoin wallet as capital I