How the quilt will look after washing depends on a couple of factors:
1. Were the fabrics prewashed, before the quilt was constructed? If the answer is yes, the fabrics will not shrink with an additional washing and keep their current shape.
2. What type of batting was used? Cotton batting tends to give the crinkled look of antique quilts. Polyester batting tends to keep the as constructed look, but may look a bit more puffy after washing.