Remember to make your planning flexible. Things happen during a school day- fire drills, assemblies, stoned students stumbling into class and falling over, snipers...you get the picture. It does get easier as you go along- I expect one day in about 22 years I'll have it right- and then its time to retire. It doesn't take most people that long, but I am slow.... Sounds like you have pretty normal concerns to me. Good job on being prepared- but again, don't set yourself up in stone 'cause if you do, then something might throw you off. Your first year will be quite a learning experience- be sure to learn from it, but don't let it beat you. My first year was unpleasant, but I survived and carried on- next year will be number 8.Lastly, is it normal to write everything down for your lesson plan that you are going to say,
A good piece of advice, incidentally, from a man I met in a barber shop who had retired from teaching many years ago, concerning the students- "Be very clear about what you expect from them, and most of them will do that." It is true, and I'll pass it along so you can do the same.
Good luck on your first year!