I went to check another univerity in North of Germany. It is uni of Paderborn in the city named Paderborn. A lot happened during this trip, which i'll write later. The university turned out to be very good and people are good as well. Let's see what happens.
btw, on the way back, something funny happened. I puchased the train ticket and saw a train on the plateform ready to leave. I ran and got on it. I tried to check the train number but it was nowhere written. I asked a boy onboard and he said that this is the correct train and that he is going to the same immediate destination (mostly you have to switch trains during a long journey). But after an hour, i came to know that it was going in opposite direction (towards North - Hannover city). Then i came back to Paderborn and restarted my journey to my city (cologne) westwards.