What size do I wear at Wet Seal?

At Wet Seal, I plan on buying a skirt. It’s not loose or flowy, so exact measurements are pretty important. In general I wear a 3 or 5 (or the 3/5 clothes) in clothes. Thing is, there is no measurements for skirts on the site.
So I have about 36-37 inch hips, and I don’t know what size to buy.
The sizes are like 1-3-5-7, etc.
So, if anyone has shopped at Wet Seal, what size do you think would fit me?
Oh, I’m ordering online, btw.

Hi, I’ve just started modelling and I need to think of lots of different poses for a catwalk runway. ?

I obviously already know that old, basic, put-your-hands-on-your-hips-and-kinda-pose but I need different and creative poses that are NOT inapropriate and don’t make me look like an idiot. I am doing a catwalk runway so it has to look proffessional and hot! For all those fashion gals out there, PLEASE HELP ME! xoxo