I used to pack heavy after the cruise pull out clothes from the suitcase that was not even worn. I do not do that anymore. I pack light now. Although I do have 2 boys I think packing for a preteen or teen girl would be alittle different. This is what each boy packs for a 7 nite cruise -
1 pair dress pants
2 dress shirt
6 shirts - tshirts etc
pj's socks and undies
and sneakers, shorts and shirt that is worn to the airport
Plus I always buy them a tshirt on the ship.