Invest some of it, yeah. You have to realize how frigging volatile bitcoin is, though. There's nothing that says we have to stay at or break above $2500. We could be back down to $1500 or lower by tomorrow. Do I think that's going to happen? No, but it's possible. So if you're young and don't have a retirement plan and have extra money to play with, do it. But be ready to lose money...and hope you don't.
I wouldn't put too much into crypto.
Yes, that is right. I totally agree with you. There is no way that we would ever know what will happen to bitcoin, like if its price will go higher or lower. There is always a risk of losing your money so I would advice you not to invest all of it. The best thing to do is to invest some and profit from it.