I am a pre-washer, but not after the pieces are cut. I think you might have a mess on your hands.
I pre-wash because my dear Granny taught me to, about 40 years ago. Since then, I have learned that most shrinkage occurs in a hot dryer. It is the pounding that shrinks the fabric. If a quilter doesn't pre-wash, it will probably shrink after the first washing, and then you have the fabric and batting and back all shrink at different degrees, and if you use polyester thread, that thread doesn't shrink, so it gets tighter as the cloth shrinks. Over time it can cut through a fiber slightly.
Some wonderful quilter here at the forum gave the best advise ever! Now I do what she does; baste the edges of the quilt before you wash and dry, then you don't have the fabric all knotted up from the fraying. When you remove the basting, you slip the point of your snips under a few threads, cut, then turn over and find the thread to pull and it all comes out easily.