how are you attaching your piece?
My first dresdon ( 30 years ago) I had a machine sewed edge before attaching to quilt top.
now, have learned, if hand sewing onto fabric, that was not neccessary.. just up to style of your quilting too.
I don't think there is a wrong answer. more of an answer, how not to have frayed edges to protect your beautiful work.
Good luck !
Ell