What should I do?????

What your mom will like is the fact that the ring came from you and that you took time to do something for her. The yellow ring will remind your mom of her childhood but the past is the past. The blue ring is prettier and it says this is now, forget about what happened before. Another thing is I don't think your mom will want the yellow ring cause it's like a replacement. If your dog dies, getting another dog just won't cut it. Especially if it's the exact same dog. This relates to your ring dilemma cause your trying to get your mom a replacement ring. Give her something new. Get her the blue ring...