Learn so much that you can convince yourself not to invest at all. Then maybe you're close to being ready to invest.
it doesnt make sense
I think he means play devil's advocate with oneself. Learn about all of the potential things that could go wrong.... Government intervention, wallet theft, inflation, competing currencies, and so on.
Exactly. You make money in markets by not losing it. You don't lose it by controlling risk. To control risk, you need to be aware of the knowable risks involved.