"Ausländerbehörde" VS "Bürgerbüro"

Today I am so happy. I got an email from Flensburg University about restricted admission which I receive for studying European Studies there. Then, here I am now: learning the information from its website carefully as a newcomer candidate. After had learned the obligation before come to Germany, I finally arrived in the section what I need to do when arrive there. It mentions that there's a difference for students from EU and students from non-EU. For Non-EU students, they should register for residence permit at Ausländerbehörde,"Non-EU students must register with the local authorities within 7 days of their arrival and obtain a residence permit (Aufenthaltserlaubnis)". Meanwhile registration of residence for EU students, they should go to the City Registration Office "Bürgerbüro".
Now I know why my mom Au-pair brought me to the Bürgerbüro instead of Ausländerbehörde even I had mentioned to her since my coming at the first time that I must go to the local immigration office in Dachau. Perhaps I might be wrong but I think she didn't know it that I need to go to Ausländerbehörde instead of Bürgerbüro. But why did she make a mistake like that? Easy answer. Because she didn't have any Au-pair inspite of a German nanny so she didn't have any experience yet for that. Furthermore, it was understandable that she used her experience handling her nanny related with documents and/or registration to Bürgerbüro for me also, which is a mistake of course.


I just can smile now. Life is an adventure!