Life is being stretch, as a consequence this will widen the time line and in part the illusion of women having children later on in life.
The common age of women having children will peak around 34 to 40, my best guess, we are also aging slower.
There's a longer and longer list for not having kids. Some is good. Some is quite sad.
Bad
-environmental concerns
-cost of living pressure/child support cost
-worries for kids future
Good
-woman's empowerment
-hobbies/leisure time
-break away from "tradition"
Some of those can probably be combined.