It looks like there are white blocks and mint green blocks. How about adding white border and quilting with that pretty deeper pink thread. Maybe even a decorative stitch in scallop shape. How wide is the present border? I would unstitch (rip out😒
the bottom portion of the crosses to allow some room to sew the border seam. Since there is presently no binding, I would not bother adding one either. I would cut a strip of white fabric 18" wide by length of side. I would fold and iron at 8 1/2" in from the one side of the 18" edge. That will give 1/2" Seam allowance and 8" in the front of quilt. On the opposite edge, I would turn under 3/4". That will give the backside 8" from the bottom edge + 1/2" above + 3/4" to backside. I would cut strip of batting 8 1/2" (8"+ 1/2" seam allowance) and sew batting and unpressed edge to front of quilt top, flip material down and to back, iron, carefully pin, and SID. Backing will be stitched down with SID. Then I would pin the batting down and do the quilting.