gridlock violation--how bad is it?

Today was a bad day, I got this first ticket in my 15 years driving.
I was not aware of this violation at all until a policeman told me to pull over my car. He was standing nearby this intersection (about 30yards) and waving to each car like a traffic director. It was drizzling, rush hour, many many cars, every car was slow moving. I definitely started to cross the intersection at green light, but due to the slow merge at this side street I was going to, I might have not completely crossed the street yet when the light became red and I had to stop since the cars in front of me stopped to wait for the merge and the policeman's directing, but I did not block the traffic.

The policeman told me if I did not want to pay the fine, I can go to the court and I might won if I had a good record which I do. Any suggestions? would this increase my insurrance fee?
I am in MA.

many thanks!