My 7yo daughter was also very opinionated about her dress style. She wanted a "poofy" skirt and straps instead of sleeves (she said spaghetti straps and I said "NO"). So, I checked out my bookmarked list and found this tutorial. She totally approved! The straps are the minimum 1" wide allowed in the school dress code, so it should be OK to wear to school if she wants, and the skirt is two full widths of the fabric- so it is very "poofy."
Thanks for bearing with me as I showed off my girlies' Easter dresses the past few days! Happy Easter!!!