Fuck yeah she was. She can make a clear thought out decision and still be a nut. Sane people don't make choices like that.
Sounds far saner than choosing to suffer the constant indignities and suffering inherent in old age and the dying process.
My Mother who is also a Nurse cared for hey dying Mother who suffered for years at the hands of a rare cancer. My Mum says if she had her time again she would have euthanized her Mother after she requested her to do so, but she relented as she feared the consequences. But watching those you love suffer deeply is most likely more painful than dealing with them no longer being there. My Mother is now 72, has a lot of issues, bladder cancer (now in remission) severe osteoarthritis (drastically restricting her mobility) a decade old aneurysm and severe tinnitus (which she claims is the thing that drives her the most insane) and a host of other mild ailments. She fears what else will happen in the obvious decline she is now in. Although I would prefer my Mother to stick around, I would never begrudge her the choice to check out if she so chooses.