I think you are too "old" if:
- You have to maintain optionality. "Well, if it doesn't work, I'll just go back to Google". More on this here:
- You can't afford to do it. You have to find a way, whether it's raising capital or being ramen profitable. I know this can be hard.
- You're a bit too tired to start from scratch. This can happen at 30, 40, 50, or 90. But it happens to entrepreneurs, at least, most of us. At some point, you can't do the $0-$1m revenue phase again.
- You see too much risk. A variant of optionality. You have to see the white space you are attacking with crystal clarity. This doesn't mean you are unaware of the odds or the risks. You just have to see something that others don't see, that means the risks (in your mind at least) are far lower than others might think.
- You can't recruit and inspire the early team -- that importantly, is good enough. You'll need to recruit at least a small team before there's any sane reason to join you. Can you recruit a good enough team at this stage? Most people can't. They end up bringing in the people they can get, but if they aren't a good enough programmer, a good enough whatever ... they fail. You can't do a start-up without the minimum quality team necessary to get to first base.
Experience helps a lot in B2B and SaaS. 50 can be a great time to start. But as the years go on, sometimes (not always), the bullets above become bigger challenges. Sometimes though, it gets easier.
Also, I'll say across the 20 investments I've made after being a founder myself ... I have no idea how old any of the founders are that I've invested in. I don't care.
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