Idk, I'd think there's a lot of room there. For one, everyone dies eventually and she never really specified how far in the future that would be. Another thing could be her dying and leaving a corpse though being reanimated with a new body. Then there's how all these 'this is how the future will be' things never really seem to pan out or sync up in the DCU'. Add in a dash of 'he might just be lying'(albeit I doubt it) and voilĂ .