Well, there was also a study done on that at some point, I remember reading about it. Basically what they found is that women have a harder time determining penis size than men do. They know what they like size wise, but they are bad at determining the exact measurements just from looking at a penis. There hasn't been nearly as much research done on female penis size preferences as has been done on male penis size, but there have been a few studies. One study found that the majority of women don't care that much about size and think that men place too much emphasis on size, the same study as I recall said that women care more about girth than length, meaning that a somewhat short, fat penis is preferable to a longer, thinner penis. There was another study done where they 3D printed like 30 different penis like dildos with various sizes and asked a group of sexually active women to pick out their ideal size for a one night stand and their ideal size for a long term relationship. The average size of the penis they picked for casual sex was 6.4 inches long by 5 inches girth, while the average size of the long term relationship penis they picked was slightly smaller at 6.3 inches long by 4.8 inches girth.

I don't know, many of my female friends say they have been with big guys at some point

Typical female can take dick up to 16-18 centimeters before they start feeling pain, and most women I know, consider this size "big", because this is what they feel "hits the end/bottom".

Many women are interested in what big feels like, which is why guys with big dicks are often in demand for casual sex - meaning many women have been with the same big guys at some point. In a relationship a big dick isn't usually benefical, because the typical reason to have sex in a relationship isn't because of feeling horny, but to satisfy a need, which isn't fun at all if sex hurts. Quite the same as hitting IUD with your penis when having sex - not a problem once or twice, but you lose interest if it happens every time you have sex.