Out of state ticket from NH :(

Around early November, my girlfriend from California decided to visit me in Mass. I pushed back the court date to around May. We decided to make a trip to NH to see the White Mountains and explore. I'm from California so I do not have a car here, we rented a ZipCar for the whole day. I got pulled over on I-93 going "89 on a 70 speed limit". I'm not sure if I went 89 but I do remember going 60-70 and having cars loop around me to pass. A car was tailing me so I sped up momentarily but not that much. When I got pulled over the cop basically said nothing and handed me the ticket for going too fast. This is my first speeding ticket and I'm so confused on my situation from it being an out of state ticket, does the ZipCar change anything, is it worth fighting for, and how do I fight it. I'm a full time college student paying for my own tuition so it will be hard for me to get transportation back to NH as well as pay the $400 ticket, the court date is also on a day of my final. Thanks in advance guys.