Sketchbook Shorts for Girls – Sizing?

I'm about to enter the dreaded/ugly world of uniform sewing. We have a pretty strict requirement....no sneaking in any cute linings, etc. Navy blue and white. The end. For those of you who have made the sketchbook shorts for girls, did you use their regular size, or did you size down? They have to be mid-thigh length, but I know my kid will not go for shorts that are at all baggy.