23 years old looking for accomodation in Vienna from March till June 2016

I'm 23 years old and I'm looking for an accomodation in Vienna. I am going to stay there from the 1st of March 2016 to the 30th of June 2016 for my thesis in Chemistry. I'm a bit shy but friendly and I consider myself a calm and tidy person (I lived for 5 years in Trieste with the same roommates and we didn't get any problem). I'm looking for a room in Vienna, single or double doesn't really matter. Here in Trieste I live in a double room for example.