What did you say controls the students' age ranges now? Having high-school students that are 19 and 20 seems silly.
Where I live, people leave second-level education around 17-18 years old.
I had a look into the DefaultGameConfig and there's only an entry for Minimum Age.

Never mind, found them. In case anyone's interested, they're in:
Schools\NormalSchool\PopulationData\Parameters

Does not work on an existing game. Edit before starting.

Now to see if I can figure out how to manipulate population generation.
Nope. Can't seem to figure this one out. Probably hardcoded.
Given that there exists a PTA proposal for a "Unisex" school, it's too far down the line for people that want to play a single gender school.

By the way, "Unisex" means all sexes, the default setting for Smallville High.
Monogendered is single gender.

I believe the gender ratio can be changed by changing the weights in the files in PopulationData\Sources.

In the config folder of each school there is a 'minimum age' that overrides any and all other checks during generation. So a change would need to be made both to the population generation file and to the config file.
Quite a bit of population generation happens in Config now that I'm looking at it, not gender though.

Quote from: Name3773 on Jun 03, 2022, 06:46 PMI believe the gender ratio can be changed by changing the weights in the files in PopulationData\Sources.

Yup, this was indeed it. Thank you!

I made a bunch of changes to the files of the 1.10.1.2 release to make the student ages 14-19 and adults start at 20, plus modified a bunch of the special characters so they are in the new student ranges, mostly pretty randomly but picking a new age and sliding the birth year around.

I have started the game with these files and have not run into any problems but I have seen a 20 year old student within the first month, but didn't think to check the birthday in debug to see if they just aged up in game.

I also tried to play with the ratios of male and female students going from 45/45/10 to 35/55/10 M/F/Futa.

On another note entirely, there should be a way to graduate a senior class of older students at some point during the 2 year game period to open up slots for more younger students and let the older ones work on the adult population group mind. I suppose the right approach would be for the game to do a sort of the potential student pool right after generation and after assigning the must enroll students, start grabbing the older students first so they could age out and graduate. Then maintain that list and use it to enroll the new weekly students, leaving the younger students for year 2.

Anyway if I can, here are the modified files.