I saw it. It is not a movie about romance. It is about independance and family relationships. Merida is not girly at all. Her mother, in the contrary, is girly. I think you can watch it, but I can't predict if you will like it or not.
Well, I'm a thirteen year old girl that isn't girly at all, and I think you should just skip it and watch TDKR. But only after you've seen the first two, of course.