Is it sometimes NOT a good idea to put off having kids?

I know that people say less educated people usually have their kids young and have loads of them, while more educated people put off having kids until they're comfortable with their careers. So let's say the average high school dropout have their first kid at age 16-17, and by age 25 have like 4 or 5 kids. While the Bachelor's degree person has their first kid in their late 20's to early 30's. Some even later than that. But think about it. By the time an educated person would be at the top of their careers, they would be more than likely in their mid-late 30's. A woman's chance of conceiving biologically starts to lower after the age of 35. By the time a woman is 40 her chances of conceiving are even more lower, and even if she does get pregnant she has a high chance of giving birth to a child with birth defects. These are usually the same women who put their careers first instead of wanting to raise a family. They look down on less educated people who have kids they didn't save financially on, but at the same time they're crying because their child was born with a defect. Which from what I hear is not easy at all to do and take care of. Yes I understand that it's good to have some money saved up to have kids, but at the same time you don't have to have all the money in the world to raise kids either. Income also doesn't determine your parenting skills. Your thoughts?