My daughter actually wore this dress to her "Enchanted Forest" themed Prom. It's really gorgeous. She is 5'6 and wears a size 4-6, I ordered a medium but a small would have worked, too.
She's not a girly girl, but she was IN LOVE with it. She said it was light and comfortable.
The back is see-through lace so you'll have to be creative with your boobs if you care about your bra showing. lol