15 and getting investigated?

I'm 15 and a detective called my cousin asking about a person in the house that has an iphone and goes to a particular highschool(which is me). But I don't live there so they wanted to get a hold of me. But what I don't under stand is how come they didn't just trace my number instead of tracing my cousins. So my cousin called my mom, gave us the detectives number so we call them. And when we called telling her what my cousin said to us(btw my mother was speaking to her). She then asked who is the person she is speaking to and my mother said her name, an the detective said" are you the mother of (my name). So i'm guessing she already search things, and she said that they are investigating something taking place online and connects to the highschool i go to. Its about the media and she's targeting people that has iphones i guess. But that was all she said and nothing else. So now I have to meet up with her a the police station on tuesday! Can someone please explain to me what's going on, I didn't do anything I have no bad pictures on my phone I only go on instagram, and browse through facebook once in a while. And haven't post anything in a month. So I'm confused, btw i'm a girl.

It is a good sign of innocence if you go to the police station voluntarily.
Unless you are arrested, you do not have to go at all.
It's unusual for the police to do their work by telephone.
And you should not go until you know what it is about.
However, you must have your parents present, and refuse to answer any question at all except through a lawyer. (Though typically, you'll probably won't be able to stop yourself from stupidly saying lots)

It's unusual for the police to do their work by telephone. How did the woman show you her ID?

Plain and simple in this case as is in any police case ALWAYS and I mean ALWAYS exercise your 5th Amendment rights. Nobody is truly innocent. You have done something or the police would not be trying to track you down. Exercising your 5th amendment right will save you from self incrimination. Even if the police get angry and if you are not under arrest they can't do a single thing to you for exercising your rights.

Let this be a learning lesson in how to handle police matters.