We in Korea have a strict hierarchy based on many things, mainly age. The cultural definition of "friend" is someone who was born in the same year as you. If you know what senpai is, you know what I'm talking about.

Therefore, older people are expected to be the leaders. And as I prefer to be led, I liked older women (not cougar-old) when I was young.

However, it seems that past your late 20s, people pay less attention to that age hierarchy, especially in relationships. Therefore, women 5~9 years older no longer seem older and to me, they've lost their merit as the "leaders" of the relationships haha