This is what tracking means -- that you get "sorted" into either they "Gymnasium", "Realschule", or "Hauptschule" track after fourth grade. However, this is not what happens in Finland. In Finland, everybody gets the same basic education until age 16, then picks either general upper secondary or vocational upper secondary education (note that vocational upper secondary education does not bar you from attending a university, despite what the GP thinks).
However, what he mostly doesn't seem to realize is that Germany (or Finland, for this matter) does not really have the same type of highly competitive admission process for its universities as the United States [1].
For example, the Karlsruhe Institute of Technology, one of the best German universities to study computer science at (according to a recent ranking, the best), has open admission for its CS Bachelor program.
[1] The Bologna Process americanized the system a bit, but it's still mostly about managing supply and demand. If you can't hack it, you won't graduate, but admission is not particularly selective, especially not at the Bachelor level.