That happens with every startup I've ever seen, within months of starting it up--regardless of the quality of the startup. I don't think this is a very good way to measure startup potential.
You, as the entrepreneur, better be damned excited about your idea and your team and your product. So excited, in fact, that you talk about it all the damned time to everyone. Of course, talking is rare...you don't talk to many people during that phase, because you're busy working. But nonetheless, if your girlfriend isn't sick of hearing about what you're working on, then you might not be passionate enough about it to pull it off.
You, as the entrepreneur, better be damned excited about your idea and your team and your product. So excited, in fact, that you talk about it all the damned time to everyone. Of course, talking is rare...you don't talk to many people during that phase, because you're busy working. But nonetheless, if your girlfriend isn't sick of hearing about what you're working on, then you might not be passionate enough about it to pull it off.