I've never really understood the desire to be immortal myself. The idea of both wanting to live forever in some form and wanting to stay young forever just sounds exhausting. It's one of those desires that people think they want but when you actually stop to think about what it actually means, it's really awful. One of the reasons that life is bearable is because it's going to end soon. One of the main concerns of fiction is how do we make a life of 85 years or so meaningful.