Then I remembered that I have these things called "hips."
Cute idea, but not for me. So, I threw the cut pillowcase into my scrap fabric pile, until I realized that my 5-year-old could surely fit into a skirt made from it. Also, she LOVES skirts and dresses right now, and this would make a perfect play skirt, since I won't care if it gets dirty (it was free!).
Lining up the ruffled edge of the pillowcase with a skirt that already fits her, I cut the top of the pillowcase off, leaving a little over an inch as my waist-line.
The ruffle on this pillowcase makes it such an easy project, because the hemline is already finished and decorative.
On the cut edge, I folded down twice and ironed.
Then, I sewed all the way around the waist, leaving a small opening for the elastic to be inserted. (Notice that I was too lazy to switch the thread from my last project, but I figured that when it was worn, her shirt would cover this line.)
After cutting a piece of elastic that was the same size as my daughter's waist, I attached safety pins to either end of it. This helps it to slide through easily.
She loves her new prairie skirt, and I love that the whole project, start to finish, took 15 minutes!