It is quite normal to have a medical rep in the OR. They do not assist in the hands on surgery, but know a great deal. I can understand you being nervous being her first one. I would only hope that she has done a great deal with another surgeon and not just a few practices on a cadavor. Did you ask her how much hands on experince she has? If she does THRs she at least is use to placing the acetabular cup, but in resurfacing the angle is very critical.
Using an inexpiernced surgeon does not mean there will be disaster, but the odds are 4% of the people will have problems or revisions. That only means 4 out of 100 people will have problems. That is not a great risk, but in most cases I try to get people to use the very experinced surgeons so they are not a statistic.
You have to do what you have to do. If there is no other choice and you can't travel, then you will be her first resurfacing. Every surgeon had a first BHR patient and they have to find them somewhere.
So I would say that you need to go into the surgery with a positive attitude or cancel and get one of the more expiernced surgeons. If you have chosen her, then have faith in her.
Good Luck.
Pat