Thank you so much for your order and review.
Egreis is 5'6 which is slightly taller than you by half an inch, but she's wearing a size Small and as you can see on the photos, it isn't too short on the back. She did wear tights.
The other model, is 5'10 and she wore a size XS (main model on the site) and we don't believe it is too short on her either.
This however doesn't mean much, because everyone has different proportions even if they may be of same height. Two people that are 5'6 for example can look completely different. One may have a longer torso the other may have longer legs so that would change where a dress falls completely.
I believe in your case, it would have been best to size up to get that 'dress' look. Our size Large model for example, wore it with jeans and a turtleneck because on her size L was too short to wear as a dress. She would have to size up to get that extra length to be able to wear it as a dress.
Hope this helps explain it a bit.