Thanks for all the helpful and honest comments! I really appreciate it.
I'm like 75% sure it'll fit, but I decided to look online and found a dress that I LOVE. LOVE. LOVE. Why oh why did I look? Then I ran down to JC Penney to try it on, but they didn't have it in the store. Meanwhile, I tried on a few other dresses - and get this - all the 20W's were TOO BIG! The 18W's fit just right, but nothing tripped my trigger. So, here's the dress I like. I have these super-duper cute wedges that fit now. They are silk peep toes in a black and white geometric design. Let's see if I can find them online.
Anyhow, here's the dress. Right now it's on sale for $35. I haven't checked what the shipping is. I know it's pretty cheap - it's just deciding whether I can justify it when it's basically to wear once.
It's my favorite color (that I confess I think I look good in with my blond hair and tannish skin) and my favorite cut, highlighting my little waist and nice bust and downplaying my hips and thighs:
And here are the shoes: