Virginia Tam, what a prize package you loved, so sorry she's gone form your life now. I can't imagine anything worst than losing a child. We are supposed to she our children into adulthood before we ourselves go first.
I swear by the love of our children, there is nothing so strong.
The last time I had a transplant my wife was so fearful of my dying (I came very close the 1st time too). I knew my daughter (she's alot like your daughter form the sounds of Andie) & wife would get past losing me but I knew my son couldn't & wouldn't, he has his demons that he deals with the best he can. I told my son I wouldn't die until I knew he was fine &could be left on his own. The doctors told my wife to ask me if I wanted to keep on fighting & she camme in & told me that if I needded to go it was ok & that I could go. I told her I wasn't going any where until Gabe (that's my son) was in a better place & that I wasn't even close to braking that promise I made him. I came through that failed transplant then 12 day coma & another liver transplant. What we will do for our kids.
All the could've, should've, would've's doesn't change a mother's love, not many of us has the gift of foresight, we're all to blessed with more than enough 20/20 hindsight though.
From the sounds of your Andie, she lived life as full as she pleased, right from the start & it sounds as if she died on her own terms too. Sounds like she was asking you to let her do just that.

I'm so sorry that you feel as if you have something to blame yourself for, I'm not in your shoes but it only sounds that you had a one of kind daughter & she would have it her way no matter what you think you could've done for her.
I hope she lives on forever in the hearts of those that loved her

Barry