Accident While Backing Up - Who is at Fault
 

My question involves an injury that occurred in the state of: New Jersey

Earlier today I was driving through a parking lot when a truck had backed into me. I did not slow down due to the thought of having the right away and even used the horn to warn the backing up vehicle, but was backed into and got a dent on the passenger side door of my car. The truck suffered damage to the driver's side bumper. Now, the person in the accident is offering me to pay for the damages up upon coming to a sort of agreement otherwise, an insurance claim will go through and my insurance will go up. I'm really worried that it may be my fault.