Education is a federal function so there might be differences from each state but generalization is possible. At the age of 3-6,children may attend kindergarten. After that they have to compulsorily attend school for 9-10 years. The (Grundschule) or elementary school comprised of 1st to 4th grade where all subjects taught are equal. After 4th grade they are separated according to their academic ability and wishes of their families. They are to choose from, Hauptschule(the least academic), Realschule(leads to higher vocational school), Gymnasium(leads to a degree) and Gesamtschule (comprehensive school, which not all states have this).
(source:wikipedia)I felt that it's too early to decide which path should the pupils should take. There can be students who are late bloomers, that was my concern, but then these 3 different school mentioned have all the possibilities that will lead students to a degree if one wanted to have it. On the other hand, if they want to pursue their school of choice, at earlier age they can already land a job and enjoy life outside school. Not a bad system, I think.
One more thing that made the German school system,including universities meritorious is it's available for FREE. Yes, it's available to all children, including those children of bonafide expatriates.