I suspect some kind of brain uploading or simulating will be created in ones lifetime. Its likely in order to be this kind of immortal you would only be able to exist near or around the invention of brain uploads or simulations.
Any other time you would not be born, or experience existence.
It doesn't just affect decisions you make, but also all things around you. Decisions others make and events that happen. Everything is acting on probability, you just only exist in the universes where.. well.. you exist.
The shitty thing is in this scenario you don't get to choose the option to be immortal or not, you just are. You get as much choice in the matter as how much choice you have in being born, that is to say, none.