Hi Arianna, I hope i am not waaay too late for that suggestions. What is helpful when travelling is to hook up with local couchsurfers
www.couchsurfing.org . I did that in Portugal and its an awesome way to connect with the local habits (CSers come in all sorts of age, its not only youngsters as one might assume). I like Berlin, anything at Prenzlauer Berg is cool.
If you have been in Berlin already, how did you enjoy it? Its big, right :-) Scary at first. Oh and the Berlin Zoo is a must see if not for the animals then the architecture alone should let you gasp for air :-).
Kreuzberg is the new "alternative" Szene (before it was Prenzlauer Berg, which is now a little more boho and hipster and chic).
Berlin is changing so much and i usually only stay a day or two myself so unfortunately i have not been able to dive into the culture as much as i would have wanted to.
But i had an awesome experience about 10 years ago, when Prenzlauer Berg was still alternative: I was searching for a place to stay in Prenzelberg, and one lady that i did not know (she was a bartender) just called one friend who wanted to go to Vienna and said i cna stay in her apartment (it was a typical eastern Berlin apartment, i think they don`t exist like that anymore, all small and stuff :-)))....) and in return i organized her a place to stay in Vienna for free at a friends house. The awesome thing was, that the woman did not know me, and about 10 minutes!!!! later , me, a complete stranger, had her apartment key in my hands and her trust.
Houseswapping at its best :-)). And stories like that are kinda typical of the Berlin spirit in the alternative culture especially. :-)) (lol)