The thing that's good about the grandmapocalypse is popping the wrinklers for their cookies but not much else (at least what i think). You can always just turn it off, it's not a big thing and you can turn it back on any time. Later into the game there's some other things related to the apocalypse, mainly the seasons and season switcher, so don't forget about it just yet.
Tdlr: if you want to stop it just do it you can always turn it back on again