I am confused, if that square is 1", your seam allowance looks larger than 1/4". It is kind of hard for me to tell. I am really not sure as I have never made one, it just looks larger than 1/4". I really don't starch much, but I wonder if this is one of those patterns where it would really help.
Good luck, I am off to bed. There will be lots of ladies on in several hours and they will be able to help you.