Speeding in School Zone, No Lights Flashing

My question involves a traffic ticket from the state of: Tennessee Hi! So this is kind of long so I’ll start at the beginning, I was driving through a school zone that says 15 when the lights aren’t flashing, and it’s normally 35. So I was going about 25-30 when the cop directing traffic around the school stopped me in the middle of the road and asked me why I was going fast, so I told him the lights weren’t flashing. He said it doesn’t matter so he looked at my license and kept it. He told me to park in the parking lot of the middle school so I did, and then told my to drive up to the high school a few hundred feet away without giving me my license. He then gave me the ticket 45 mins later at school for going 35 in a 15. How could he pace me while he was directing traffic? Plus can he take my license for that long and the lights weren’t flashing?

Speeding in School Zone, No Lights Flashing