My maternal Aunty was grey by 13, and my paternal Grandad went grey overnight almost, at 25-ish, after watching his brother and nephew fall of a cliff and drown. Apparently the stress caused it He's as white as snow, and has always been that way since i've been alive.

I got my first greys in highschool, and now at nearly 26 years, I have skunk streaks!! Yuk!!