According to who? Cite the scientific studies that support your claim.
Why would women reach their sexual peak long after they've lost their fertility? Perhaps older women are more comfortable with sex, and have come to terms with men's unrelenting need for it, but there is no evidence that 40 year old women desire sex more than younger women. One would expect the opposite. It could be a misattribution error on your part. Your experience with young women has been negative, but it is not because they don't desire lots of sex or are not good at sex. It's simply that they don't desire sex with you.
There will come a time when I'm old and unattractive to hot young women. I dread the thought but it's inescapable. We all get old and ugly. You're already there, blackrock. When that day comes for me, young women will mock my old ass, just as I did to my elders during my youth, and they to theirs in years past.