In Europe College is ~11 to ~17yo, Uni is after this. I think 11 to 17 is high school in the US, so as an European, the way it's portrayed in the game doesn't shock me. They're in some kind of school for older teens where stuff is teached, that's enough for me.
Since the story seems set in Western Europe or the United States I have always assumed the US model of school.
Ages 0-3 Nursery / Day Care
Ages 4-5 Pre-Kindergarten and Kindergarten respectively
Ages 6-11 (grades 1-5) Elementary School
Ages 12-15 ( 6th grade, 7th grade, 8th grade, 9th grade((Freshman=9th grade)) Middle School or Jr. High School
Ages 16, 17 to turning 18 High School- Sophomore, Junior, and Senior Years of High School. * some High Schools include Freshman year aka 9th grade in High School. Mine did, but my kid's did not/does not.
College and University in the US are the same thing, with the name of the school being the only difference. There are Junior Colleges which do not offer the full Baccalaureate degree, but offer something called an Associates Degree (2 year schooling)
In both cases of College and University, you have Freshman year which is generally general studies with some focus on your degree program if chosen, and Sophomore, Junior and Senior years in College and University are more focused on your Baccalaureate Degree in your chosen program.
Graduate School has Master's Programs, Doctor of Philosophy, Medicine, Jurisprudence just to name the major Doctoral Programs.
So College=University in US based games and I think most Western European based games as well.
Peace