Don't get upset over a mistake. We all over the age of 60 start making such stupid quilting mistakes. I always try to measure twice before I cut but then there is that one you just don't see coming. For heaven sake, don't cry. I would go with the narrower binding. No one will notice. I have even sewn smaller strips together on a double folded binding making sure the seam is on the inside. Just take a break or and come back later to try to pick up the pieces.