This is an article that you need to read critically, beyond the headline.
Even a few paragraphs down they say this:
> The optimal age to freeze eggs varies depending on the source and metric, but almost all sources agree it's sometime between 19 and 26.
So there's some heavy bias inserted already into the title.
The next chart shows a peak around 19, but if you read the fine print it's not a chart about eggs at all. The subtitle says it shows:
> probability of getting pregnant for couples not on birth control
Not the quality of eggs frozen. They're saying one thing in text and showing a chart of something else. If you can't imagine why couples in their early 20s might have a higher rate of pregnancy than couples in their 50s then you might want to think a little deeper about the factors that go into that.
The writeup then goes into polygenic embryo screening, which then jumps to improving IQ by selecting embryos, which gets to their final argument which is that it's easier to collect more eggs when younger. So freezing a lot of eggs when you're younger allows for more boosting of your child's IQ through genetic screening based on a company called Herasight's data. Herasight has been widely criticized for overselling their abilities. Also, why do so many rationalist writeups end up back at a conversation about genetics and IQ?