The bridal shop ordered a dress that is not my size!?

Ok.... My Brother and Soon to be Sister in law moved their wedding up. I went in and got measured and paid for my dress. She told me I was a size 12. I got home looked up the measurments for alfred angelo dresses and there is no way I will fit in that dress. According to their chart a size 12 is 38 1/2 bust 29 1/2 waist and 41 inch hips. I am all of those except the waist. I am a 32-33 inch waist. How do they expect me to fit in this dress?? I am a little worried about it since the wedding was moved up to March from June. The woman told me I was in between a size 12 and 14 and that she was going to order the 12. There are no refunds and the dresses do not come in till March 12th and the wedding is on March 30th. Should I call there and talk to the lady or just hope she knows her job?? On top of it. My other sister in law is a little bit bigger than me and they ordered her a size 12 also. I know there is about a inch on each side to take out. But that still will not make it fit. Help