I finished it and it will work. I will definitely make changes to any future mat covers, but this was a good first attempt. I didn't take photos as I was making it, but it is easy enough. Make three rectangles and sew them together :)
I made the first one out of a light weight flannel. Here is the finished mat.
All folded up.
Pillow. I wanted to make the pillow AND the blanket out of this fabric, but it was the end of the bolt and I only had enough for the pillow. I do have a little left over than I might make into a "blankie" for C.
Button closure on the bottom. When the mat is unfolded, the buttons face down, that way the littles are less likely to mess with them during nap time.
Little model. She wasn't very cooperative, she had just woken up from her nap.
I wanted to sew a ribbon into the seams that would tie the mat closed, but I thought twice about it after I saw how long the ties would have to be. I am sure the teachers appreciate the change in my design so that it doesn't come with a ready made noose. I am happy with the finished product. I believe it has Charlotte's seal of approval, which is really all that matters, right?