I'd go with a half-ponytail, then the ends all curled. Half-ponytail being all the hair from in front of her ears in one high ponytail, maybe then tied with a with a matching dark blue ribbon, then with the ends of all her hair curled, it will create sort of layers of curls cascading down her back (conveniently covering any acne that shows up as well). Pretty dress, and you know there will be a demand for pictures!