How did she ruin it? Is the quilting just poorly done or did she get it skewed, puckered, etc?
I'm just curious how a LA could actually ruin a quilt.
For people who aren't into quilting, the actual "quilting" part is less important that the colors of it, usually. So, I'd say go ahead and give it to your niece if it is the colors that she wanted. Before I started quilting, I never ever noticed the actual "quilting designs" in things.