What an awesome find! I've never seen that design, either.
Usually you "age" a quilt by the fabrics used in it. I can't see your fabrics real well, but I think I'm seeing different colors of the same prints... which would mean it was made from yardage rather than clothing scraps. So I'm not thinking that it is as old as some of you are saying. But, who cares? It's a gorgeous quilt, meticulously made, and definitely a treasure! Enjoy it.