I'm also 22 and I know that as I get older, I'll start to favour black (I already do now more than a few years ago!) and I really like black and amber together...
I agree that it is definately a personality thing! plus I think amber is a very soft type of jewel (LOL, I know it's not a jewel like a stone, but you know what I mean!) and so it really suits older women.
Diamonds can look very hard and cold on older ladies, whereas amber doesnt.
For me it is a combination of age and personality - it really comes into it's own on older ladies and could look very sexy on the right young person, for sure!