Aw man, the poor girl. I know you're feeling it too, these decisions are so heartbreakingly painful and stay that way for a long time after you make them. I think as long as you stay focused on her being comfortable, you will know when the time has come. We got the final word for my baby and had 3 more amazing months with him before it got to be too much and he was no longer living comfortably. I am glad I didn't act rashly, as those last months were something I still cherish. When he stopped wagging his tail and muttering his little happy noises to me, I knew. Though I didn't know how much pain he had been silently suffering through, until the vet gave him a huge dose of pain meds so he wouldn't have to go while still in pain. That confirmed my decision and gave me such relief, knowing I was doing the right thing for him too. Your cat will tell you when it is time, it is your job to listen and not draw it out for her bc you're sad or afraid. Do the right thing for your companion and you will at least have that peace.