A lot of Devs simply rename the the teachers to professors, and the school to a college even though it acts nothing like a college. It'll annoy some players but it'd be easier done than rewriting the story so that they're actually in college.
Also, while you're reworking the game, it might be a good idea to give a good think to how far into the incest you actually want to go. MC has already gotten with his adopted sister, though she doesn't know they're not blood related. The game seems to heavily imply that the adopted mom will also join the harem. All well and good, though I think adopted is still classed as incest for the powers that be. You've recently introduced MCs biological mother and (twin?) sister. It's unclear whether you have any plans of them joining the harem but that would certainly anger the powers that be if they were to find out.
