I recently went through a 9-week financial 'university' offered by Dave Ramsey (which I'd highly recommend to anyone, especially those under 30). All of us agreed in the end; it's knowledge that should be taught in high school. Not as an elective, but as a requirement to graduate. Given the results of compound interest, why shouldn't we be required to save earlier in life instead of later? The best time to save for retirement is before you have a mortgage.
Afterwards, my wife and I discussed that if we had known then what we know now, we'd had made different choices. But since decisions are based on implicit bias (which is largely outside of our conscious control), it's an unfair self-judgment. In hindsight, we'll always determine that we would have made different choices. Those who look back on life and say they wouldn't have changed a thing understand this. They know that regret is wasted energy because you can't go back and change things. Life is what it is. All you can do is take this newfound knowledge and try to apply it to your future choices.
However... just knowing what we should do is only half the battle. It's what we do with the knowledge we gain that matters. I was drawn to the course because many people who stick with it successfully pay off their mortgages early. I do not want to be saddled with a mortgage payment until I die!