The right time to work on a startup is any time when you have identified a real problem to solve through your overall work and personal experience. When something occurs to you that seems clearly obvious as a need, backed up hopefully by some data from potential customers.
The wrong time to work on a startup is when you just have a vague desire to work on a startup but don't have the passion for solving a specific problem but just feel a vague pull towards startups. In that case, you are much better off joining someone else's startup.
You can make long hours work out with family life and having kids, people do it all the time who are not involved with startups but work multiple jobs, lawyers who work long hours, etc.
Long hours per se is not the issue, spending those hours on the right, productive thing is the issue.
The wrong time to work on a startup is when you just have a vague desire to work on a startup but don't have the passion for solving a specific problem but just feel a vague pull towards startups. In that case, you are much better off joining someone else's startup.
You can make long hours work out with family life and having kids, people do it all the time who are not involved with startups but work multiple jobs, lawyers who work long hours, etc.
Long hours per se is not the issue, spending those hours on the right, productive thing is the issue.