But don't get trapped working for a startup and kidding yourself that their success is your success. If it isn't your company you probably don't own a meaningful amount of stock- it's never worth busting your gut over.
I hear this line a lot on HN and frankly, I have to call bullshit on it.
A real startup (which I define as "a currently small business with large, untapped potential market") with a real business, (which I define as "make something you can sell to people for money"), is a great place to find work at with a real chance to make significant amount of money (which I define as, "I can take 1/2/3 years off to do whatever I like without worrying about paying the rent") in case of success. And the odds of that level of success are not bad if you're smart about choosing your company carefully.
How do I know ? Personal experience on multiple occasions.
(btw, note that my definition does not include "this website/mobile-app we hope will catch Marissa Meyer's eye for a quick $X0 Million flip.)
That is however very different from the type of startup that we usually talk about here, which does not an have an well established businesses model already.
Given just this information, it's still possible that people who start companies in their twenties are more likely to be successful; but most people who start companies are 40+. I don't necessarily expect that to be the case, but do you happen to know offhand?
The minute you have kids your discretionary free time drops massively (in many cases to zero for a while, especially if both parents work). Plus your view of your finances change - you have other little people depending on you so that steady income from that steady job looks really appealing.
If you're not someone who wants to set up on their own, that's great. Personally I have other priorities too (damn pesty kids...), but I'd say if you don't think you want to do it in your early / mid 20s when you have energy and time, you probably need to accept you actually don't want to do it at all.
But they showed faith in me when I really needed a job, they hired me on the day of the interview and even paid me early when I was about to be homeless (again.)
I love the culture at my company, I love table tennis at lunch and Bacon Fridays, I enjoy my work and the people I'm with. Regardless of where I want to be in 5 years, why would I give all that up for a minor chance at being rich?
It's a good question. Why would you? Maybe it's just because it's a vast challenge. There's plenty of time though, don't worry.
Sometimes, people grow apart from the environment they're in - for what I've seen and thought, that's probably when we're open for a larger challenge and with that, some new risk/opportunities.