Ya know I am 29 and I have had grey hair since I was 12, ya 12. I do dye mine but when the grey starts to appear again people tell me to just leave it let it grow out. I know a lot of young guys that are all grey and they are still hot. So ya I find it attractive especially when they don't die it just shows how confident they are.
I'm 19 so I don't fit in the category you are asking the question to. But I can tell you that from my perspective, a older man's grey hair is very sexy. It conveys the feeling of wisdom and experience. It's definitely attractive. Why hide the natural occurrences in your body?