Think of her as "going away to school".....
You did the right thing. She is probably asleep right now, having played with her furry friend all day long. She will be fine. Really. You couldn't ask for a better solution.
If I have learned anything about pet ownership it is that it must work for the pet and the family.
Maybe, just maybe, you can try her again, if things change....after you return from Germany. She should be out of her puppy stage by then. You just never know.
Sleep tightly, knowing that you did the right thing.:)