How old where you when you found your first grey hair?

I'm 18, and I found one yesterday. This saddens me because my hair is one of my best features. The other men in my family didn't really start getting grey hair until they were in their 40's and didn't start losing their hair until their late 60's. I hope I don't have a bunch of grey hairs by my mid 20's.. I would be so insecure.