I had major streaks of gray by the age of 23 and my sister was totally gray at 17! Our parents on the other hand didn't gray until they both were in their 70's. We say that instead of giving our parents gray hair, they gave it to us and if you knew our parents, you'd totally understand. My ex-SIL's hair was almost completely white in her 20's and it earned her the nickname "Snowball".