Hi, Stacey! When we updated all of our iOS games last year to work properly with iOS 11, we made them universal apps, rather than separate apps for iPhone and iPad. The (old) iPad versions won't work with iOS 11. What you want to look for is the game that is titled simply, "Virtual Villagers 2."
The universal versions work fine on iOS 11, and I've tested them on iOS 12, as well, with no problems.