As they keep saying: don't invest more than you afford to lose :) I personally don't think that the bubble will burst anytime soon, but it's going to be more and more difficult to make money here. Joining as early as possible is definitely the way to do it and risks are minimal.

If you bought Bitcoin when it was $100 - you could've cashed out when it dropped from $5,000 to $4,000 and still make a ton of profit. In the end, if you're early enough to get profits even after a crash, you're safe. If not, it's a risk worth taking in my opinion :) Especially if it's something you believe in!