Maternity clothes

Hello all.

Right now I am 7 weeks along, my very first pregnancy.

But when I will be 14 weeks along my only sibling is getting married.

I know up until 27 weeks I will have work parties that require cocktail dresses.

Do I go ahead and get a maternity dress for the wedding, not knowing if I will be showing? Or do I get a regular dress?

And where can I get a good maternity dress that won't break the bank? I've looked at Target, Old Navy, JC Penny, but have found nothing that I even remotely liked.