Over generalization is when you generalize to a group larger than is applicable. This is the same group and a very accurate generalization on his part.
It was an over generalization because I'm an exception: further along in life and YC was a great option.
It is probably true that people with more fiduciary responsibilities have more to think about when taking the plunge, but that is a tautology. People with more responsibility have more responsibility.
My point is that even if you have a house, cars, kid(s), student loans, etc. you can do it. It just takes a bit of planning a maybe a little help from your friends & family.