I think it's still a matter of matching your body type and going all the way with the costume. Someone 40 could look better than someone 16 so long as they get the make-up correct and fit the style.
That said, a friend suggested I do lolita recently. I'm a guy, and whilst I did try a girly makeover, I do think I'm a bit too old (and too tall!) for lolita! (here's my makeover photo
- what do you think?)