HI,
Before you give up, try wetting the quilt and letting it dry on its on.
See if you can figure out a way to gently stretch the edges as it drives. I am thinking a long arm quilter could tell you how to do that.
Be thankful that you washed it and had the "slighter smaller" experience. Image if that happened to the person that you gave it too. I have washed a lot of things that got smaller and just wet them again and do a little stretching. Beautiful quilt. Just shows all of us that life is not perfect and we aren't either.
Dianne