it can't get much easier than this.
take 1 bandana, cut in half. sew up the 2 side seams to make a tube. overlock the raw (cut) edge then fold to make the casing for your waist elastic. guess how big your daughter's waist is (because she is fast asleep) then thread your elastic through the casing & sew ends together. go have a coffee and twiddle your fingers until said daughter wakes up so you can try on your newly sewn skirt.