I broke out the sewing machine after 7+ years and dusted it off. After finding a simple skirt to try out I got cracking...
First I measured my little Brooke around the waist then added 10 inches then divide by 4.
Then I measured how long I wanted the skirt to be (since this is my 5 year old down to her knees was appropriate) then added 3.5 inches.
I cut out her rectangles and got sewing. After 3ish hours I had a finished skirt for my Brooke to wear and I think she rocks it!