cottonmouth snake

Ok, so I was in my dad’s car at his work. My mom was in her car next to me. My cousin, brother, and friend were in the car with my mom. I was by myself listening to music. Then, I look to my left in the side mirror of the car, and I saw a snake. It looked about 3 or 4 feet long. I was freaking out rolling down the window and yelling my to my cousin. It rolled down the window and said, “what.” I told him there was a snake and I looked back and it wasn’t there. We both got out and saw it under a car 20 feet away. That means Its fast. So, we checked what time it is to see if my dad was off work or not.