Aging happens to all of us hun, and mostly at varying rates, you could have been an unlucky one who goes grey at 18....
It sounds like you don't have a lot to worry about. I'd advise keeping a good diet and regular exercise, and against taking anything you don't need to. You never know what damage you may cause.
http://www.bbc.co.uk/news/health-15238610
Thank you for the article, Anti-Flag!
Thanks to all of you for sharing. I guess I won't take any supplements, I fear the unknown impact.