For me, it has definitely changed. Starting in my teens as a senior I was attracted to younger guys. I also tended to have friends who were a couple years younger than me. By the age of 35 I think the youngest was 10 years younger than me, but I had someone that was 19 that had a crush on me.
After 40 I totally gave up on marriage but I became attracted to somebody 11 years older than me. I was surprised. But I think it was his youthfulness. I also think he had a big attraction to younger women. But one time when we went on a date I noticed the age difference when someone said I looked like his daughter.
6 years after having giving up on marriage and entering online dating this past year, I really found a variation. Older guys didn't repulse me quite as much, partially because I had had a boyfriend for 2 months that was 11 years older. As far as the dates I've been on this year, probably the two longest engagements of time spent on dates was with someone who was 3 years younger, and for some reason he felt a lot younger because he called himself a boy and he definitely needs some growing up. The one that I ended up going out that with it was older, this time was 12 years older. He had a lot of the maturity, engagement and old fashioned pursuit (picking up the phone instead of texting), and just something different that made me feel beautiful. so because of these experiences I have been a lot more open to older guys that I was before 40. Now someone 10 years younger than me just seems way too young. I don't know what this all means, but it's crazy to think how much my taste could change in two decades in guys. I think maybe in my younger years I just wasn't ready to settle down and I wanted the guy who also wasn't, even though I said I wanted to marry.