Going to a party soon with a lot of architects. Bit terrified as architects tend to be far richer and more stylish than me (though the hosts are lovely etc). I'm 43, about 5 feet 9 in and a size 14. Ideally thinking of a chic black midi or maxi dress. I shop a lot in Cos and Arket, Me&Em or Sezane when feeling flush. Any ideas?! Hoping for something that is simple but won't make me feel like a frump!