Want My Ex Girlfriend Back!?

My girlfriend and I dated for 2 years, and we just broke up. We broke up because we were arguing and said 'ill just go date someone else then'. It was not meant to be said at all, and since my girlfriend is very serious she took it very seriously and dumped me. Now I think this is a very dumb reason to break up, but I am still madly inlove with her and she told me she still loves me. Her exact reason for dumping me was because I don't treat her with respect and I am just an ***hole to her all the time. I told her that I have no intentions to act like that anymore because I've never meant it before. So now, I talked to her yesterday and she was very mad and upset, as was I and she said she wanted to wait until our final exams are done (which is why I think she is so stressed out) and talk, but I have no idea when she'll even try talking to me. I don't want to move on and I have no intentions to, but maybe do you think that she's overeacting because of her stress levels because of exams? She said she just wants time, and I told her thats fine I just want you to know that I am changing positively for you, and I want to know what I should say to her to make her truly believe me. I told her everything from the heart a few days ago and she called me 'manipulative' and that really hurt. If, when, we do talk, should their be set rules like no arguing or what? I just miss her and I want her back, we dated for 26 months and its something I want to continue doing.. and we are both 17.