What is happening to my hair?!?

Well, I died my hair early in the winter but the dye quickly faded and went back to my natural blonde colour. But I have blackish gray roots and some parts of it in my hair and my eyebrows are now that colour to. I want to be a blonde, it really suites me (not because I'm dumb but I like it) :) Is my hair turning gray already? Black? I'm too young to be old! Sorry, that sounded really weird . . .