it would seem awfully risky to put so much of a retirement fund in to such a volatile instrument.
It also depends on what size your retirement fund is. If it's $10,000, well, unless you invest most of it in a risky asset with high returns (like Bitcoin), you can be pretty damn sure you'll have to work yourself all the way into the grave. If you do invest in Bitcoin, there is still a good chance there would be no retirement for you, but at least there is some hope.