Sorry about your little "mistake" but your quilt is so lovely that I think I would just make the last two rows look like the "mistake" rows and put it at the top to balance it. Only you will know? But of course you have to live with it so you need to do what you need to do. Can you tell I hate to rip especially once I am that far along? That 15 year old is a lucky person to get this quilt!