Hello! I feel for what you're going through, and I know you'll find your way through it one day at a time. I'm a caregiver for my father, who also has an advanced cancer.
Moms know everything. You have to be kidding if you think you're keeping it from her. The second you're born, I think they get superpowers. In my opinion, it's always better to tell the people closest to you unless they're so young that they can't ask questions. It's easy to feel that you're protecting people by not telling them, but I have always found that I'm more at ease when I know I'm getting the whole story and I don't need to worry about surprises, even if the news stinks. I'm now at a point where I go with him for everything at his request. But he has other health issues and could easily have not told me what's going on. You may not want to go through the emotions of telling her, or to hurt her. But I think there's more emotional distress in feeling that you're maybe not being told the whole truth. Also, holding that back doesn't change the reality that she will learn sooner or later. I'm glad I know what's going on, and that he's able to talk to me about anything. If I survive my dad, I feel that knowing now is making it easier on me in the long run, and I think for him, he is much more at ease knowing he can be open and honest about everything he's experiencing. When you're ready, I think you can just say you want to be upfront about everything, just as you would want her to be open with you about her health. No one knows the future for sure-- not even the doctors. and so you go through it together one day at a time, and you can still have a lot of good time left. Have a good cry together and let her be a mom and you be a daughter. I'm closer to my dad now than I think I ever was.
Sooner or later, we are all equal in that we all change, and have to walk through that doorway. No one is exempt, or hated. Hate is a human thing. I don't know anyone who knows what God is, or explain how it works. But it can't be all bad if it made something so wonderful that we don't want it to ever change. It's amazing that we last as long as we do, or that we're here at all in these bodies.