I would go 60 x 60 so she can use it as she grows older then it can become a quilt to read with, watch tv, talk to new friends on phone when she is a teen. :-) My daughter still has her orginial quilt balled up on her bed and gets very cranky when you try to put it up. She got it when she was 4 and she is 13 now with 2 other quilts that are just not as good as her "comfy" one.