vera wang pleated tulle flutter back wedding gown

i'm an indecisive person and purchased this dress on a whim. now i can't return it. size 18, fits us size 14/16. it's a beautiful dress, but i've just changed my mind. "Soft vertical ruffles of tulle float over a layer of delicate Chantilly lace to lend airy texture to this plus-size sheath wedding dress. The deep-V back is trimmed with a fluttering cascade of pleated tulle, and the entire look is finished with a removable grosgrain ribbon."