I don't think you'll really know what looks good on you until you try it on. Strapless dresses tend to look good on most people. I say just go with an open mind, try on the dresses you like and see what they look like on your body. I know I've bought dresses before that I never thought would look good on me and they looked great, and vice versa. Forget what your friend's mother said. Go with someone you trust and you'll find something that will look fabulous! Btw...40 is the new 30