I not only marvel at the idea, but also struggle with the fact that I have one daughter that I think will be extremely distraught when I go, and another that might fair even worse because she refuses to accept that I am of the age where it can be truthfully said that one has one foot in the grave that the other on a banana peal.
Just a heads up, once you make the decision to be a parent, it never stops and has the same permanency as a Supreme Court judge. You see them occasionally making what you thought would and did turn out to be a mistake but you cannot correct them because they are adults and have the same rights to live their own lives as I insisted on having for myself so many years ago. I define it this way, with one daughter turning 50 in a couple weeks and the other just two years behind that I am their Father, but I am no longer their Daddy. I cannot stop them, all I can do is offer my advice (if they ask for it) and then it is out of my hands. Let me tell you they will always be your children, but in name only. That, however, doesn't mean that you no longer have the urge to protect them and want to attempt to fix their problems and feel the fear when they get sick or wander off the path.