Haha you and me are in the same boat. I can’t speak Korean that well either. >< A lot of this blog is just stuff I remember from high school to be completely honest.
To answer your question, yeah it sounds correct. There’s a spelling error at the end; it should be “같이 살아요”. Though I know language classes are all about word/sentence counting, so if you need/want to, you can put “우리 집에 다섯 사람 같이 살아요” before that sentence. Totally unnecessary, but if your Korean teacher is anything like mine, it might come in handy. =P