Determination of Fault: Backed into a Car Illegally Parked in My Driveway (in My Blind Spot)

My question involves a traffic ticket from the state of: Kansas

Hello. I backed out of my garage, and my right rear fender/bumper hit a car that was parked (but still running) on the side of my driveway. He was parked in my blindspot, so I was unable to see his car there as I backed out.
It was a high school kid helping his girlfriend scrape her car. He readily admitted it was his fault and thought no one was home at my place--this is a duplex with an adjacent driveway to the duplex next door. So he decided to park in my driveway.

Police said because it was private property, they could only facilitate us exchanging info. I took pics and the police printout to my insurance agent. Shortly after an adjustor called me. I am shocked to learn I may be at fault because I hit the stationary car even though he parked on my property and I was unable to see his car out my rear view mirror.

My car has right rear fender/bumper damage, and his car has headlight and front passenger side damage.

Am I screwed?
:nightmare:

Determination of Fault: Backed into a Car Illegally Parked in My Driveway (in My Blind Spot)