Modesty in dress is a cultural thing, whether we like it or not. Was she showing Laura Bush amounts of knee, or Tina Turner amounts of knee? I’m a bit concerned that you may think that anything that shows knee qualifies as a mini skirt. True mini skirts take some careful wearing to not show underpants. Depending on the length of her legs, the cut of the dress, and how modest she is when she sits, I would think that the amount of leg that is being shown in the Senate would be okay.
Oh, and lose words and phrases like “deviant”, “outlandish”, “disrespectful of our Lord”, and “manifested by demons”. Our Lord did not have too many nice things to say at the look-down-their-nose crowd.
Did anything like that come out of Our Lord’s mouth when he met the woman at the well… and don’t fool yourself about why she was there at midday, and not with the other women. Be quite sure that no one would use “prim” to describe her. He chose to strike up a conversation with her, and never condemned her, not once. How did he talk to the woman caught in adultery? That is a bit worse than showing too much leg. He didn’t condemn her. He only told her to avoid that sin in the future. In other words, if you were to put on Christ, your girlfriend would not have been attacked, and she would be forgiven by now. Chances are, she would be taking a close look at her wardrobe, and not blowing fire out of her nostrils.
Examine yourself, and then go apologize. Oh, and if you feel you have to bring up her behavior, the correct form is “I still think your skirt was too short, but I was a jerk”, NOT “I was a jerk, but I still your skirt was too short.” The second is an excuse for yourself, not an apology to her.
Finally… allow yourself forgiveness, too. You value her purity. That is a good thing. Our insecurities have a tendency to put a little Pharisee in all of us. But in the future, tell that demon to get lost.