“100 In A 60, Reduced To 89 In A 60...help! What Should I Do!”

So here's my scenario, it would be of great help to get some input and some suggestions because I really don't know what to do!

I'm a teenager and this is my first violation. I was charged with doing 100km/h in a 60. The 80 sign was about 150 m in front of where I was charged with the offence. I believed that that area was an 80 and not a 60 because it was part of HWY 2. The officer was in his car travelling the other way on the same road, turned his car around and followed me very, very closely for about 45 seconds before he put his lights on to notify me that I was being pulled over. I had a photo copy of my insurance and registration and he refused to accept it. At the time I was not thinking very clearly, a family member had passed away a few days before so I had been having a really bad few days, and when I told him about that and the fact that I really didn't know the area well he said "everyone has an excuse" and proceeded to give me the ticket for the speeding which is $395 and 4 demerit points. He gave me a break on the insurance and registration and allowed me to turn it into the police station the following day. The next day I went to speak with the crown prosecutor and he said that he would make a plea with me that is 29 over which is a $160 fine and 3 demerit points. I just want to know what chances I have of reducing the demerit points. I'm really worried about my insurance skyrocketing.

Any help or suggestions on what I should do or how I should fight it would be greatly appreciated.

Thanks Again.

demerit points are issued ONLY by the MTO upon a conviction..........the officer/prosecutor/court have no control over points