I say it's all about being appropriate. I think a bikini at 47 (or any age) is pushing it unless you are seriously in shape, and I think 51 is a little old for a ponytail (or at least the high cheerleader-ish one I'm picturing). Oh, and there's no max age for high boots, and you can wear stilettos till you can't walk anymore!
I think I'm more concerned with girls being too *young* for these styles than too old...does that show that I'm getting old?!
Am I way off too? What do you think?