Be mindful that when shopping for a gown, you might have to go up a size or two, or three, depending on the designer. All designers go by a different sizing chart, so you might be a 10 in one company, whereas you might be a 14 in another company, depending on their standards.
Be sure to wear your undergarments during your sizing. Use good posture, as this can affect your measurements, believe it or not. Make sure that whoever is measuring you knows where to correctly measure you, and how to measure. If you are inexperienced with alterations, use a professional alterations person. Don’t call your measurements into the salon, because if the measurements are not correct, this could affect your gown’s fit, and there might not be time to re-order.