you've got a beautiful chocolate lab there. mine is 11 years old and has white hair on his face.
My girl will be 4 in March, but she has a little bit of a white "beard" on her chin already. I think it's from her plastic dog waterer - her breeder said that a plastic bowl would cause white hairs on her chin, but I would rather she had constant fresh water than a dark chin - and I can't find a stainless steel waterer other than a large outside hose-fed one.