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.