I love, love, love your design for your quilt! So simple but showcases the blocks so well it looks complicated.
I bought some Sunbonnet Sue blocks at an auction several years ago that had been done in the 40's. They were on unbleached muslin and had some age spots. I serged around each square and washed with Oxiclean and dried in the dryer.I wanted them to shrink all they were going to right off the bat to see what I had to work with. Well, some had been appliqued on the squares parralell to the selvage and some were not. After washing and drying my 14" blocks were all sizes, mostly rectangular. Some rectangles were upright some were horizonal. I was able to recut then all to 10" squares.I added 30's fabric and I had enough to make my 2 Grandaughters each a twin size quilt.
Your back ground fabric lookes like it is a much better quality than what I had to work with but you might want to serge and wash to avoid any surprises after all the work of piecing and quilting.
I can't wait to see your finished quilt!