In Denmark and many other European countries, schooling includes "college prep" programs so that students are not only well prepared for college, but they have also completed their prerequisite courses--sort of like going the the J.C. here.
Starting at age 6, students attend "regular" school for 9 or 10 years, all students together, not tracked. At 15 or 16, students decide whether they want to go to university, trade school, engineering school, art school, etc., or simply finish school and start work as a laborer. They then attend programs that prepare them for the rigorous courses they will encounter in their "higher education" training.
This system ensures that the vast majority of students stay in school until they are at least 19 or 20, that they have mastered college prerequisite skills (higher math, writing, etc.), and that they have the maturity to be responsible college students.
Having lived in Denmark and attended school there myself, as well as having watched my sister's kids go through the system, I can say with confidence that this system seems to work much better than our current one. Students stay in school, are better educated and better trained (even a shop clerk has to go through a school of higher education), and it's all FREE.
I suggest we elect Bernie Sanders and see what happens!