I did when I was 12 and asked for them. Then got sick of them and let them close, then asked again about 2 years later and again, let them close in HS because I stopped liking the feeling of having earrings in most of the time. I still do actually, and the only reason I can wear them so sporadically probably now is that I come from a "pierce the baby's ears" culture (off the boat if you will!)- not that I necessarily advocate that.
I think old enough to clean and take care of them is a good benchmark. I know a lot of really conservative women in their 30s who wear double studs come to think of it. Maybe its a reflection of the time period that we were teens, who knows, but I think most don't bat an eye at them in their classic pearls and 4 ear holes.