That is so cute. What a wonderful idea.
I made a whole crib set and accessories for my grand daughter this past spring. It turned out really cute. The Alice fabric is so adorable. I also made cloth balls and blocks of various sizes for Chloe. Now that she is big enough, she packs the small ball around all the time.
Don't you love when you make something for someone, especially the little ones, and they love it like that? It looks like your daughter is so proud of her new nap mat.