Beautiful! Are you going to fill in the corners to make it square or leave it as a hexagon? You can use more hexagons and lay them face down on top of the last row, machine sew the outside edge and turn them right side out and hand stitch the rest of the hexagon to the backing. You can also applique the whole hexagon to a white or pink background to make it square. You can lay the whole top upside down on the backing fabric and pillowcase the whole thing but that would be tricky.