would someone over 40 with kids, who doesn't have some self-provided stability be working at a startup with high risk anyway? That seems both foolish and more or less no-existent in any I'm familiar with.

I wonder if it's looking old versus actually being old? If you look like you're in your 20s but are 40 (low body fat, not many wrinkles) maybe you won't be stigmatized against as much. I'm just curious about whether it's the appearance that matters, or the number.