I think your doing a good job. As far as her coming in while lunging, you could try twirling your rope (assuming you don't use a lunge whip) toward her shoulder. Step toward her and if she doesn't move out, hit her in the shoulder with the end of your rope. Not hard, just enough to tell her to keep her distance. As far as leading, I wouldn't hold constant pressure. As soon as she takes that one step too far in front of you, pop her face and back her back up. Holding constant pressure is really just more of a nagging thing, and she will continue to ignore it and get harder on her face.