It is so heartbreaking for you to be faced with this decision. I am in tears for you. I am so very sorry.
This may not make sense right now, but just be thankful that you have had this long wonderful life with her and that now you are in a position that you can say good bye and give her this gift of her relief from suffering and send her to be with your mom, someone she has been missing for quite some time. I know how it is to try to hold on to everything you possibly can that somehow makes you feel connected to the loved ones you have lost. I have experienced this all too often lately just as you have, but the fact that you are NOT being selfish during such difficult times says so much about you. You mentioned your concern of being selfish...you are far from it. These things are
never easy and it is totally natural to not want to let go. You have a very big heart, and sometimes it takes a big heart to make the right decisions...nomatter how much they hurt. I will keep you and Flossie in my prayers.