I moved with my gf at the beginning of the year into a house from a 550 sq ft apartment. I was convinced that the dining room table was useless, and thus room for a single game, she was not. But she wanted a dog and was convinced that 550 sq ft was big enough, and I was not. Now we have a house with a yard and a full basement and two machines and one puppy later, we're both happier for it.
Moral is, you probably do have just enough space, but you won't be happy if she isn't.