How did this happen?

So lately I've been finding pure white hairs attached to my head. These are not gray, nor blond. They are white. It started happening last December when I was enmeshed in grading plagiarized papers and dealing with them, etc. So first I just thought they were stress-induced. But they continue to come. Maybe they were originally stress-induced but now my head has realized that it's easier to put out white hairs than to go to all the trouble of making them brown. In any case, I pull them out. My only concern is that I can't see the back of my head and there could be lots back there that I don't know about at all.

When did I get to be an adult? Someone should have consulted me about this before letting it happen.