Go in to that school with confidence, own it. Don't be a bully, but make sure you're strong, confident(even if you're not), most ppl starting high school proably feel the same as you, so get a little advantage, walk in that school, quick , longish steps, and with a straight back, greet ppl.. looks like you got confidence, and when it looks like you have, it will come to you...
Good luck on your first day!
