Hello!

I'm sorry I don't speak German well

Your plan fits me perfectly, both the time and all the rest :-) I'm 23 male, planning to go from Hannover to Macedonia (I'm basically going home), following Eurovelo 7, then Eurovelo 6 and finally Eurovelo 11, so my route should basically be:
Hannover, Prague, Vienna, Budapest, Belgrade, down to Macedonia. The Eurovelo tracks are mostly flat (no more than 6% grade), should have nice scenery and not much traffic.

Note I've never done such a long distance on a bike, only at most one day excursions of max 200km biking. Right now I'm looking to buy a proper touring bike, I only have a road bike which is not very suitable.

Let me know in case you like this route, it would certainly be nicer to travel with some company :-)