I know who's gonna die first

Hey Mom, guess what?  I know who's gonna die first in our family.  (mom) 'Oh really, who?'  Well, Dad is going to because he's' the oldest.  My sister will die last because she's the youngest.  (mom) 'It doesn't really work like that.'  Well unless we all died on the same day, then we would all go to heaven at the same time!