I don't know if there's an ideal age to have kids, but 18 has always seemed way too young to me. I know a lot of people who had kids at that age who, while they love their kids, deeply regret not waiting.
You also make it sound like starting a business from home in your early 20's with kids is somehow more feasible than working a stable job. That doesn't really make sense, especially when you just talked about 90% of startups failing.
Author waited and also regrets. My point is that having kids early is much easier and cheaper, because it is at peak physical health.
Baby requires too much attention and prevents work in normal 9-5 job with fixed schedule and meetings. But it leaves enough "holes" in time table to work on something.
You also make it sound like starting a business from home in your early 20's with kids is somehow more feasible than working a stable job. That doesn't really make sense, especially when you just talked about 90% of startups failing.