For example, if you graduate with an engineering degree, can code, and don't have any grave medical conditions or loans to repay, I'd wholeheartedly encourage trying to start a company if you want to. It's risky in that the company would have a 95% chance of failing, but in that case you still learn a lot and it's fairly easy to land a job if you keep up your technical skills.
If you're stably married, your partner earns a high income in a stable job, and is supportive, that's another case where I'd say go for it, take the calculated risk.
In a lot of other cases, such as if you're knee deep in student debt, or (live in the US + have a medical condition + not a lot of savings), I'd advise building up a modest amount of savings first.
It really depends.