I didn't say that.
In fact, I believe that to be false.

The guy who analyzed the data from OkCupid wrote a book called Dataclysm. Their dataset is much much bigger than that of any scientific study ever done and lacks the bias that most scientific studies have (the subject group usually contain a disproportionate amount of students, resulting in the WIERD bias).

Some of the data is presented here:
Matchmaker, Matchmaker, Make Me A Spreadsheet | FiveThirtyEight

It turns out, women find males that are very close to their age the most attractive. That means that what a woman is physically attracted to changes as she ages.

For males, it looks very different. Males of all ages agree; woman are most attractive at age 20 to 21.

Now obviously a 50 year old male doesn't want a 20 year old GF. That's not what this about. It is about the age where the female physical attractiveness peaks, as judged by males. Considering this dataset is like 10 to 50 million, it is extremely reliable.

I think knowing where you peak in physical attractiveness is pretty important for females to know when they want to optimize their dating/mating strategy.
I mean, I think we can all agree that if you have a higher mating value yourself, it is also more likely to get a partner with a high mating value.

As for my personal opinion, I won't give it as it is not important. If you are interested in it, give me a PM.