NDCA has some rules regarding preteen costuming. They're not long and they're not onerous. See?
(1) Skirt with top or simple dress with attached under garment or leotard top with full skirt
(a) Plain or pleated with minimum 1 to maximum 3 half circles. One plain simple underskirt allowed which is no larger or longer than top layer, and is the same or similar color as the outer skirt
(b) No uneven hem lines, use of boning, frills, splits, openings, fishing line, "lettuce edging", etc
(c) Length of skirt must not be shorter than 3 inches above the knee cap and no longer than 1 inch below the knee cap
(a) Boat, high neck, v-neck, sweetheart, 'peter pan' collar, and regular collar are allowed
(a) Long, short, elbow length, cap, puff. or sleeveless styles are allowed
(b) Cannot be replaced by trimmings, frills, or edging on the shoulder line
(c) No "finger loops" allowed
(a) Fabrics MUST be only one color throughout
(b) No glitter, metallic thread, or fabric creating 'light or pattern effects'
(c) No use of feathers, fringes, bows, belts, frills or sequins
(d) No flesh color fabric
(e) Any use of color coordinated 'see through' fabric must be lined from waist to shoulder; for use on arms no lining is needed
(a) Heel height not to exceed 1.5 inches, and must be block heel style if a dance shoe
(a) No use of arm bands, chokers or headbands
(b) No decoration is allowed on dress or in hair
(c) No jewelry is allowed
(d) No makeup allowed
(e) Use of fake eyelashes, fake fingernails, colored or glitter hairspray is forbidden
(f) Socks: White ankle socks or flesh colored pantyhose must be worn
(g) No fishnet tights
(h) Gathering or shirring on the bodice is not allowed.
The finished product: