First of all idea is nice.
But as for game I'm not sure if you would make it in time. Even with Renpy (visual novel programing soft) it will take a while as far as I checked for Dating sim we were going to make here... Still at beginning stage XD.
I think you should better go with School AU universe. Making boys older it's hard and after a lot drawing lately I still didn't figure out how to do that XD, 16 years old Hight school is a lot easier.
Good luck and I'm looking forward your work.