20 years old guy,looking for a single bedroom

I'm a Portuguese student with 20 years old and I'm making a double degree (Business Management and Bank Management & Financial markets. I'm likeable, educate and organize person, used to leaving alone and in community, always with the ability to maintain friendly relations with people with whom I have shared apartment. I'm a rugby player and sport fan in general. I'm looking for accommodations with a single room and with shared facilities like: Bathroom kitchen with washing machine and dryer and located in central berlin (near charlie checkpoint). I will give preference also to locations which are near underground station or bus station.