My DH and I have been invited to a black tie event, and I don't have a long dress. I have some really nice dresses, but they're short. Do I have to have a long dress? Am hoping I don't have to buy one, as this is the first time we've ever been invited to such a thing, and we've been married almost 30 years. I mean, really...

I'm counting on some smart advice, ladies. Help!