I am a lvl 63 hanging around Outlands and all I want to do is quest, but I keep getting tagged by the horde. Apparently this is PvP and I want PvE so they don't attack me, but how do I switch it. I right-clicked on my character's face to pull up the engage/disengage option, but it says disengage already. I don't want to fight the opposing faction, I just want to quest in peace. I don't know how it got turned on (being a total noob when I started without a manual to read for help), but HOW CAN I TURN IT OFF?? ;_;

Unless you're inside your own territories, you will be attacked regardless if you're flagged for PvP or not.  Since you cannot transfer characters from a PvP realm to a PvE realm, you'll have to either live with it or start another character at a PvE realm.  Alternatively, ask someone to quest with you to lessen the chance an opposing faction attacks.

dont forget that if you are on a pve realm and you enable pvp (for example to do the hellfire tower quest) you need to disable it again. and once disabled it takes 5 minutes non-pvp (dont fight back) before you are actually back on pve mode

If you are in a PvP server, click select server and select a PvE one.

If you are on a PvE server, do what the above poster said.