MazdaMP, as far as I understand it (don't sue me if INS disagrees!) --

1) you don't need an interview before you come, because Germany is in the Visa Waiver Program
2) you don't need one after you come, unless you've been to the suspicious Muslim countries listed earlier and can't give a good reason why
3) see number 1
4) see number 2
5) see number 1

So you don't have much to worry about... unless there are special requirements for the F-1 visa itself.