I'm 21 and I've noticed over the past year I've been growing more and more gray hairs. Last spring I noticed a few and from then until now I've been growing them pretty much all over my head. My hairdresser even told me I have so many on one side that I have streaks of grays. My hair is shaved all the around except on top and my natural color almost black. I can definitely see my grays on my sides and it seems like they grow faster than my dark hairs.

Does stress cause grays to come earlier? If I decide to grow my hair completely out (the sides) will my grays grow faster? I would like to grow it out natural but would it look strange that I'm young but with a lot of streaks and spots of grays?