you can start a family at 19, and you can start a family at 35. Either way, yes, it's going to change your entrepreneurial options. I personally see the question of how you have a business with children to be largely orthogonal to the question of what age it is optimal to have a business.

Also, if I owned my home and had a million in stock (I'm 37 and got my first coding gig at 17, so a million in the bank is totally reasonable if I was frugal and invested in low-cost broad index funds, and there have been several points during that time where a bay-area abode could be had for very reasonable money.) Then maybe, I mean if the corporation was setup correctly so that liability didn't fall through to me, then maybe I wouldn't have to move back in mom's basement when my business fails.

I chose not to have children, and I don't regret that choice, but let me tell you, if I did want children? it would be a lot easier to do had I used my 20s to build up resources rather than trying to compete outside of my field of expertise, outside the fields where my innate abilities help me.

>Depends on when you started investing. Compounding interest is only a powerful force in your favour when (implied) interest rates are above zero.

There's no point in my life at which I could have started investing wherein I would be underwater now. No point in my parent's lives, either. if you take a 'buy and hold' approach with broad low-cost indices, you are going to have a hard time finding a date where if you bought and then sold ten years later you wouldn't have beaten inflation by a reasonable margin.

>And still: every working hour of older people is on average more expensive to give up on some startup.

This bites both ways. I can point out several mistakes I made running a business in my 20s, mistakes largely due to inexperience that had I not made those mistakes, my business would have been opportunity cost profitable and then some. Yes, I get paid more now than when I was 25, but I also produce a lot more value, and a lot of that extra value, the "wisdom" as the old people like to call it, is outside of my abilities as a unix tech or a programmer (though I'm better at those things, too.) I am worlds better socially, and have a dramatically deeper understanding of business.

(you can argue that the business skills are because I spent my 20s running a business... and you wouldn't be wrong, but I would have learned some of that working for other people, and my social skills? those are just me getting better at life, in fact I think my social skills would be better still had I kept an office job during that time, and having better social skills will help you dramatically in business.)

I personally think that my increased pay does not nearly capture my increased value. I am dramatically better than my first coding job... and I only make like 4x what I did then, and that's not counting two decades of inflation. Running a business is one way to capitalize on both your technical and your social skills.