my 36-38 year old sisters would destroy 99% of girls who are 20-22 for beauty but then again, we have dark, thick, oily complexion in our race and neither of my sisters tan, smoke, drink, eat garbage, over eat, use too much makeup or any of the other things women do to destoy their skin in the US.
it's prolly like 60% how you take care of yourself and 40% your genetics. Obviously the best races for aging well are those with thick, dark, oily skin (blacks, darker skinned hispanics, indians, middle eastern women, etc...) but how you take care of yourself is huge also. Most people in the US - past the age of like 25 - seem to stop caring how they look and just turn into total garbage.
but yes, women start to fall off around 40-50. Men do too - I think men have about a 15 year advantage. I look a 55 year old man and a 55 year old woman and the man looks significantly younger but once you hit that 60-70 range, everybody looks terrible