Being sued for child's negligence

My 7 year old daughter was playing with neighborhood children in our backyard. Some of the other children got a tire from another neighbor's yard (the neighbor has a stack of tires children frequently play with). The kids were rolling the tire back and forth and my daughter rolled it to one of the children who failed to catch it. The tire rolled several blocks and damaged a car. Am I responsible? This was clearly unintentional. I live in Massachusetts. Are parents responsible only for willful misconduct of children? Were the tires an attractive nuisance? The owner originally wanted $500 for deductible and is now suing for $1900.

Incidentally, the car owner only got one estimate, and it seems very high. Doesn't she need to get 3?