Hair, gray, grey,

Normal. Don't worry about it, you look distinguished. If you're a girl then hair dye exists. I wouldn't care too much though. Gray hair is fine through my eyes

Bear down harder when crappin

First grey hairs at 15 here. You now look wise and distinguished. Congratulations! It's the first wrinkles that suck.

Loss of melanin pigments in your hair follicle. Just go to a stylist.

Its normal for the most part.
If its bothering you that much use some hair die.. :)

My granny went totally white at 19. Shit happens and there's a lot worse in life than going prematurely grey.