I am being sued for a car accident, what should I do?

So about 10 months ago, I was practicing driving on the road with my cousin’s car and got into a car accident when turning left onto the oncoming traffic. I was 19 and holding a permit with my cousin ( licensed and over 21) sitting in the passenger seat. The traffic light was yellow and because I was still new in judging the speed and the distance of the car of oncoming traffic, it was my fault. The police came and did the paperwork, and I was the only one sent to the ER for falling unconscious in a brief period of time. The other guy was fine and the police only gave me a verbal warning. My cousin is from NY and so I am not medically covered by his car insurance, but it was fine since I had Medicaid to cover it. The problem was his insurance has no physical damage coverage, so my mom had to pay out of pocket to get his car fixed. Now 10 months later, I received a summon where the other guy sued me for sprains and muscle spasms for $15,000 or more. I don’t know what to do now.