What happens if you admit to using marijuana under pressure in court?

During an assembly at school me and some friends (3 girls including me and 1 boy) left to go get some coffee. On the way to the coffee shop there was an abandoned house that the boy and his girlfriend wanted to go in. Me and my other friend continued on to the coffee shop, saying that we didn't want to go in and eventually the boy and his girlfriend followed us instead of going into the house. We got coffee and then while sitting down in the coffee shop the boy wanted to go to the abandoned house. Everyone was following him out of the coffee shop and i ended up following. The abandoned house was boarded up except for one door in the very back and we went through the door. While we were walking through the door the boy pulls out a pipe out of a case and hands me the case to hold for him because i had a purse. I put it in my purse and he started hitting the pipe ( the marijuana was already loaded inside of the pipe) and i was like "woah" and my friend and the boys girlfriend went into one room to explore and me and the boy went into the other room. He offered me the pipe and i eventually took two hits off of it but stopped at that because i didn't want anymore. He ended up finishing the rest. About 10 minutes later we hear cops coming in the house and yelling for us to put our hands up. I was scared out of my mind so i just started walking towards them with my hands up like they said and they make us sit down and say that they smelled marijuana. they search the house and eventually come out with the boys pipe and then the cop says that if no one claims it then everyone there will get charged with paraphernalia. The boy wont fess up to it and they end up searching us. I thought i had nothing on me but then they find the case i was holding that belonged to the pipe in my purse. After that they took us outside of the abandoned house and had us sit on the curb and talked to us each indivisually. I told the cop that the case didn't belong to me and that it belonged to the pipe which also wasn't mine but he ended up writing me up for trespassing and paraphernalia. I learned later on that the boy claimed his pipe and wrote a statement, but from what i've heard, he's lied in it saying that the marijuana belonged to me. I was wondering if i still have to fight the paraphernalia charge because he still claimed it and the case for the pipe isn't enough evidence (i think) and if when i go to court if i should tell them i smoked and if i'd get charged for anything for that. My friends that were there ( the girls) said they would be sure to tell the judge that nothing there belonged to me and if i wanted, that i didn't smoke at all that day. But in the boys statement he says that i did and i was wondering if that would matter at all too? Any help at all is greatly appreciated. I"m 16 btw, living in salt lake city utah and have never as much as talked to a cop before this incident.