Hello Erica, if the child height is about 120 cm, then yes, please simply select the 'custom size'and fill up your exact body size, and our tailor will adjust the costume size to fit you. n_n
*Custom size costume doesn't charge extra cost, but the processing time will be longer than standard size costumes; for this costume in custom size, we need about extra 1-2 weeks to make it (excluding the shipping time).
If the child height is shorter than 120 cm, please submit ticket (with product link & request) to our
Support Center and let my teammate check for you directly. n_n