I'm only 16 but I think you should go with how you feel about your hair. I dye my hair, and if you dye your hair sometimes it doesn't turn out right, some people like it, others don't. That's just how some people are. Some people like my hair red, some like it blondish, some like it light brown...dark brown... etc. People always have different opinions on everything, but if you like your hair natural, I would go with that. Just do what you like. I know your best friend is being a good friend for you, but do what you want. Plus I'd be upset with what your friend said, but if you do what you like, I'd feel more better about myself.

Plus having grey hair looks great on many people. I had a teacher last year who had short gray hair with some white in it. She wasn't old either, maybe 30's/40's. But she looked amazing with her hair. Just don't be ashamed of having gray hair, it can be a beautiful thing, not always a bad thing.

Good luck!