Originally Posted by IAmCatOwned

I would just make a new quilt. She can use the old one as a snuggle quilt.

There isn't any way to add borders on a scalloped quilt without dissembling the quilt in a rather significant way. Even floating the quilt on new material requires you to disassemble the quilt so that you can applique it to the new material. No sense in going through that much work since your granddaughter will outgrow (mentally) that quilt in a couple of years as she will want 'big girl' design.