Excited that you are about to make your first quilt. You will have fun and be proud of yourself for the accomplishment!
My list of beginning items would be:
1/4" pressure foot is important,
larger cutting mat,
.45 rotary cutter,
snipper scissors for use at machine,
ergonomic seam ripper with rubber handle so it doesn't roll off machine,
a Purple Thang,
fabric scissors,
6 x 24 " ruler,
set of squares - which you have,
flower pins (flat headed),
pump spray starch (I use Niagra),
ironing surface,
iron,
2 magnetic pin cushions (one for ironing board and one near machine - don't place too close to your electronic machines),
Elmer's washable school glue,
Washable marking pen/pencils,
fabric,
batting,
backing,
template for pattern of first quilt if available.
Looks like an endless list but you probably already have most of this in your sewing room already.
Optional: chocolate and several pop-in-the-oven dinners for family on your sewing days.
Enjoy!