I am so, so, sorry that you are going through this. I lost my Scarlett to Osteo two weeks after the diagnosis. I scheduled the date with my vet when I received the diagnosis. Since I was able to let her go at home, he could have come sooner if I felt the time had come but that wasn't needed.
Those two weeks my girl got everything she wanted. I ordered in from a different place every night. She had everything she wanted. I took off her last day so that we could have that day together. All her favorite people came to say goodbye to her that day, as if she were truly a princess. We took her for a last walk in her park, with my friends strung across the intersection to hold back traffic. We all hugged her and kissed her and told her how loved she was. I held her as the vet administered the meds and just told her that I loved her with my whole heart and that she had made my life so very much better just by being a part of it.
Enjoy your love for whatever time you have left. You will know when the time has come and you will be strong. Asia has given you that.
For me, it felt as though I had ripped my heart out and that I had killed my very best friend but in some part of my heart I knew that I had done the right thing. I would say that you should believe that from the outset about yourself, you are giving her the gift of letting her go.
My heart is just breaking for you. It has been 4 1/2 years and I still cry over my lovely Scarlett.