A Chinese girl searching for a room near Ackerstrasse

Guten Tag~
My name is Siya Chen.
I'm a Chinese master student studying in the Netherlands.

From the beginning of July until the end of August,
I have applied a German language course in Berlin-Mitte.
I'm looking for a good choice, both the location (prefer districts near Mitte, safe neibourhood), the time, and the price( perferably paying the rent when i arrive in Berlin in beginning of July).
I wonder whether it is still available for me during that period.(at least two months. with possibility to extend the rent)
and whether it includes the water, electricity and internet and furniture.
Recently it is really hard for me to find a place in Berlin, even now I'm in Berlin.
I will stay in a short term airbnb room for 12 days, but after that I don't know where to go.
I have a heavy suitcase, I really don't want to rent many short terms rooms that I have to move every time.
I want to feel like home in Berlin. it is a nice city. but I just want to have a stable place.

I really love Germany, German people and German culture.
I can speak very good English, and basic level of German and Dutch.
I also speak Japanese and Chinese. I love travelling and making friends~
I am easy-going and pay attention to clean the room and I also cook super good Chinese food.
I love singing and music, as well as movies.
I wish I could have a nice place to stay in berlin and have nice memories here~

I really look forward to your reply ^^
have a nice day.

Siya.