When a woman menstruates an egg is released to keep a fresh one constantly ready for use but when she's pregnant and during early breastfeeding the process is put on hold for roughly 2 years which means up to 24 cycles are saved. There is a limited number of those eggs and when the supply ends it causes menopause.
Older women who try to get pregnant later in life often ruined their bodies with a decade or more of hormonal birth control or abortions so they can't do it even with fresher frozen eggs. Also the major beneficial changes that pregnancy cause to their health(especially mental health through changes in brain chemistry) is an important factor. Women were designed to have children early and often.
Instead of teaching this during 'sex ed' all they do is promote faggotry, modern tranny mental illness and birth control methods. Thankfully parents are starting to clue in and are burning down the schools that do this world wide. Even in repressive police states the authorities are powerless to stop it, it's not just some weirdos on the internet complaining among themselves anymore.