Rosie Ruffle Tiered Dress

I purchased this dress for an casual event and the sizing was a little vague for me. It said the model was wearing an 8, but it also said she was 5 10. I'm 5 4 and am usually a size 4 or 6. I purchased a 6 and should have bought a 4. The neck is plunging, which is fine, but because I bought it in the bigger size, it looked awful. It also came damaged, no button to close in the back. It looked like a messy off the shoulder without that button. It also came very wrinkled. Disappointing.