My project for course: Dressmaking: Draft and Sew a Shirred Dress

My project for course: Dressmaking: Draft and Sew a Shirred Dress

I really love the course and the teacher, very well explained! Looking forward for more dressmaking courses with her! She’s lovely ❤️and the course really suitable for beginners

I used a full rectangle all over,
I wonder though if anyone knows how to get rid of the extra fabric on the back? I marked it in blue (last photo) Should I make a separate upper piece for the back and attach it to the shirred rectangle part?
Idk….