I got pulled over for speeding but have marijuana on me...what should i do?

So I'm 17, and I was driving my friends car to my other friends house. On the way there I booked it and went 80...in a 55. A state trooper pulled out and turned his lights on. Me and my friends in panic looked around the car (because my friends boyfriend smokes a lot) and I found a grinder with weed in the glove compartment. So I pulled over (I didn't have my liscense on me) and I was asked to step outta the car. But anyways, the grinder was considered "mine" and he let that grinder slide. But he gave me a ticket for only speeding. First off, is this legal? Second, he said if I try to fight it, he will bring up the grinder...but isn't that illegal? Please help!!!!! Thanks!