OK, I get that you don't like the colors yourself. But, when you buy a gift for someone else, do you get them what YOU want, or do you get them what you know THEY will want? Same principle. Otherwise you are not saying "I'll make you a quilt in the colors and pattern you choose", you are saying "I'll make you a quilt, but only if I like the colors and pattern you choose". See the difference?
BTW, I agree that the colors are wonderful, and that the finished product will be gorgeous. Hang in there, you're a good sister!