First of all, welcome to YT! I cannot answer your question directly, but I can say that my first Yorkie, LacieBug, had a terminal brain disorder. I won't go into all the details, but I will tell you that each time I took her to the vet I would ask Doc -- is it time yet? And his reply was always -- Listen to her, and she will tell you.
YOU ARE NOT being selfish. It sounds like you are a warm and caring person who has the best interests of your dear dear friend at heart. I will keep her in my thoughts and prayers.
