We had a 12 year old schnauzer whom we obtained when he was 2. He was the smartest dog we ever had. When he got up in age, he got arthritis so bad he could barely stand. My parents couldn’t bring it to themselves to put him down, but finally agreed I could take him. I drove five hours from college one weekend and took him to the vet for them. I remember telling him “You did good, buddy,” as I handed him over the counter. It was difficult, but the right thing to do.
Yes. That. The last kind act of a good owner.
Also, hold her while she goes. Let her last experience be you and your love.
Edit–sorry, I jumped to the end of the thread before reading all the way through. You did good. That dog had a good death.