@ Kimberley....As for "upper age limit" it used to be 35 if the applicant goes through DAAD, the German organisation that deals with these matters. True, it is expected that one knows the language already prior to arriving at the German university. The student isn't burdened with immense tuition compared to here.
I've known only one person (42 years ago) in San Francisco at the time who did a year of study at Heidelberg since that was the only German university her university here had a program with. Because of that particular fact, she had basically no choice in choosing another university, say Bonn, Marburg, Göttingen, Freie Uni in Berlin, etc. And, familywise she wasn't of German origin, far from it.