If I were an instructor and someone came to me with a request like yours, I would see them as a driven and dedicated person who is determined to do well. I would give you access to anything that the classes prior had. I wouldn't really be overly concerned about an "advantage" because those students have access to email, too. Just like seeing some students in office hours gives them an advantage, but their advantage is their initiative. But I would definitely understand if she said something along the lines of "I respect your initiative but in the interest of fairness I think it's best to wait until class starts. I promise you will have enough time with the information to prepare for any exams." I really couldn't see her coming away with a bad impression, unless I'm missing something. Volunteering to do work to try to prepare ahead doesn't strike me as corner cutting.
