Only a few days till you ship out for your first ever real live teaching job. I envy the excitement you get to feel right now. I've already written you two notes, but here's one more before you hit the road.
Everyone worries about classroom management when they start out. I used to have nightmares about entire classes spinning completely out of control (and by "used to" I mean as recently as last summer-- and this summer isn't over yet). This is normal and natural.
Part of the trick, as I'm sure you've been told, is to focus on what you want them to do, not what you don't want them to do. In other words, I don't make my class stop screwing around so we can get to work; I get to work so that they'll stop screwing around. And I'm fudging the language-- I teach school students just like you will, and we can't "make" them do anything.
Another part of the trick is to earn respect, and it helps to give it. It also helps to know your stuff. I know it's a thing for young teachers to be told that they should be the "lead learner" or a "co-explorer" with students, but I'm pretty sure all that gets you is a room full of teenagers thinking, "Well, if he doesn't know any more than I do, why should I listen to him?" Know your stuff.
But you're a new unknown quantity, and that means in addition to the usual squirrelliness of freshmen, you'll probably be tested. The best thing I know here is what my own co-operating teacher taught me a thousand years ago, and it has held up all this time.
Don't take it personally.
To students, we are not actual people. Oh, some will eventually see us as human beings, but probably not before March or thereabouts, if ever. But mostly we are just the face of the institution, part of the Big Machine.
Complaints about things like the assignments and subject matter are just fried grousing, with a side order of checking to see if we'll come off track. When some student says, "This is just so stupid," about the work we've devoted our lives to, it's easy to hear "You're an ugly, stupid jerk" and respond accordingly. But even when students actually say, "You're a stupid ugly jerk," it's not personal. It's just an attempt to push back against the machine, to see if some sand in the gears might get the machine to leave them alone for even five minutes (because five minutes a teacher spends ranting are five minutes that the teacher doesn't spend trying to make you work).
Taking these things personally and either feeling hurt in your heart or escalating to strike back-- none of that helps.
You know who you are and what you're there to do, and you know how to pursue those goals. And when you're not sure how to handle some part of your teacherly mission, you know how to get the answers you need. Don't let the hasty words of some fourteen-year-old (words that they may not even remember tomorrow) throw you off track. Do listen-- there may be a lot for you to learn about the student-- but don't take it to heart. Don't take it personally. You know what you're doing.
I know it's hard in that first year to be sure that you know what you're doing, but you're a smart capable person, and you've trained for this (and I think we can rule out the possibility that you're hopelessly cocky). You will learn a lot this year, but you already know plenty going in. You've totally got this.