It would be nice if you could sit down together and either look through quilting magazines or on line quilts to see what style she likes. Peolple who don't quilt or love fabric sometimes have trouble explaining what they like. Does she really want a quilt? Some people don't and it is sad when someone goes to so much trouble to try to make one for them. One of my daughters thought that she wouldn't care for any quilted items, placemats or bed quilts. After a time she said well just not any flowers. So I made her contemporary looking placemats, black and lime green with actual limes on the fabric. Very simple design which she saw in one of my quilting mags. Then this year for Christmas she gave me a quilting book and showed me a table runner that she likes but wants it enlarged to a twin size quilt for her little girl! So now I know that she prefers a modern quilt mainly with solids. So my advice is take your time and visit with your step daughter about it. Eventually, she will be able to tell you what she likes. Good luck.