I often hear that if women start becoming fascinated by men or celebrities younger than they are, it shows that they are no longer young. I think that it's most likely true. Many female friends of mine and I used to be attracted mainly to men older than we were when we were in our 20s; in contrast, when we were around 30, we suddenly started having a great interest in dating men younger than we were. One of my friends would always be fascinated with men over 35 while in her early 20s; however, during her early 30s, she would always stick with having a boyfriend in his 20s, saying that men in their 30s and 40s were not attractive. Eventually, she married a man who is six years younger than her. As for male celebrities, in Japan, very popular actors and male singers in their 20s and 30s are supported by many female fans over 40.
This is just an observation; however, from a biological perspective, it can be true.