23 year old girl, looking for accomodation in Porto

Hello, my name is Costanza, I'm 23, I will be in porto for Erasmus from september to february, I'm looking for a room with a double bed or if single with enough space for an air mattress (better with private bathroom) and the possibility to host in my room my mom or my boyfriend if they come to vist me for 1 week or less ocasionally during my erasmus period. I'm looking for anywhere near FCUP (Faculty of Sciences) or downtown! I would like to stay in a house with other young students! I'm a non smoker.