My dadLet's Demons in this world and demons in your world are two different things. Vampires in this world and vampires in your world are two different things. You want to learn how to excorise a demon and send it's sorry ass back to hell? There are classes for that at the apartment complex. Want to learn how to defend yourself? There are classes for that too.
You become a hunter, there is no school. There is no social life. There isn't extracurrics. This isn't Hogparts where we teach you everything you need to know in the safety of a big, nice castle. You pick, you choose. There isn't a magic wand to make the fuck-ups go away. How are you going to expect to get from town to town with possessions of weapons that would get you life in the back of your truck? Can you even drive?
I'm sorry that things sucked that much for you. Here things are different. I don't know where the authorities were in your world that they didn't notice a kid fighting demons. But here people ask questions about two dudes, who are over eighteen. Nevermind a teenage girl.