Which, by the time it reaches us, would make me, lessee, about 800 years old?
I think the problem with that assumption is that because it takes light 649 years to travel from Betelgeuse to Earth, we are actually seeing that star as it was 649 years ago. For all we know, it could have already gone supernova and we wouldn’t know it until the light (and radiation) reached us, which could happen anytime.