In my opinion, there is no such thing as dressing your age (unless you're a 13-year-old who looks like Jodie Foster in Taxi Driver). Carine Roitfeld could go out wearing the most sheer dress, but that's ok if she pulls it off.
She does not dress like an old lady, that's ridiculous! She looks classic. People seem to say the same with Carey Mulligan. Just because they don't wear dresses above the knee, it doesn't mean they're conservative and dowdy! It's her style and I praise her for actually having personal style. It's just so rare these days. You see all these celebrities with no distinct style at all trying all these trends at once and it's just mad.