Hard to say without knowing how much I'll keep adding along the way. :D
After the current end of the main story will be a "time skip", during which you'll get to see in different phases what happens during those years, like girls announcing their pregnancy, children being born, and other stories of characters. At the end will be the big clash of the main story, and then if depends on how much will get added in the post-time skip chapter.
Having an idea for a game, starting the development, and learning the basics is pretty easy. The hardest part is to keep going and continue until you've managed to turn your ideas into an actual game.