My question involves criminal law for the state of: Pennsylvania
These are the facts: I am a 16 year-old girl. At 4 AM last night, I was riding in the backseat of car with my 16-year-old male friend driving and the owner of the car, my 19-year-old male friend in the passenger seat. We were driving on our way home, and the driver made a wrong turn, so he pulled into a church parking lot to change direction. However, once we pulled into the church parking lot, several cop cars pulled us over on accounts of "suspicious behavior." She said the car reeked of marijuana (which it did). She found a backpack in the backseat with several grams of marijuana and several pieces of paraphernalia. She also found a bowl in my pants when she searched my body. We were cooperative and polite the entire time. All three of us were charged with possession of marijuana and possession of paraphernalia. This is my first minor offense. I have never even spoken to a police officer before.
Now, for what actually went down: Everything belongs to my 16-year-old male friend. Yes, we had smoked weed earlier that night, but there is no physical proof of that. The 16-year-old male friend was originally sitting in the backseat, and left all his stuff there. A bowl was on the seat of the car, and when we were pulled over, I put the bowl in my pants quickly so that the police officer would not be able to see it while asking for license and registration. By the time she confiscated the bag from the backseat (which belonged to the 16-year-old boy and which I did not show knowledge of its contents) I was not able to remove the bowl from my pants, and so I was in possession of it. The truth of the matter is, I was a goddamn idiot and snuck out of the house to try smoking weed. There's nothing I regret more, however, what's done is done, and I am trying my best to face the consequences with the least amount of complications possible.
Today, I have already started looking for a lawyer. It's the holiday season, so it may be a while before I can find one. I have to go to court, obviously.
I am hoping to get some questions resolved and a better idea of what is going to happen from here on out since I probably won't be ale to have a lawyer inform me until after the holidays are over. A few questions include: would it be best to plead guilty or not guilty, given the facts and the truth? what process would I go through in order to request a consent decree for eventual expungement? I have a 4.7 GPA and am academically and extracurricularly very accomplished and have never done something like this before.
I really appreciate everything you all have to say. Thank you in advance.

