The apartment is huge! We came to Spain for my parents 30th wedding anniversary, 6 grown adults (parents, my husband and I and my siblings) and there was so much room for all of us.
My siblings (both in the 20s) slept super well on the bunk beds.
Laura is an awesome host, she left us a great gift basket of essentials which was a life saver until we got to the supermarket and she was super responsive. The Airbnb is in a great location, very close to the metro and some of the sites in Barcelona.