So, one of the things I've observed in 20+ years of having student teachers is the shock and surprise after the first real-non-methods class teaching.
You can't really know something until you do it. Watching someone who's been doing it for a long time doesn't really tell you much about where the stumbles and bumps will be when you begin.
I've invited former student teachers to share some first month moments to let you know how others felt along your same journey.
I remember coming home several times during my elementary placement feeling like a failure. There were hundreds of things I didn't know when I first began teaching and it was eye opening. I would walk into my apartment and wonder why my cooperating teacher could get the kids to play simple borduns with ease but I struggled, or why children need to hear a song at least six or seven times before they can begin to sing it with fluency.
As I progressed in the placement, I learned why the abovementioned situations were not successful and I learned what I needed to do to make the lessons meaningful for the students. It was only through my mistakes did I really learn anything.
Understanding that body percussion precedes instrument playing or that kids need time to process information may or may not be common knowledge to you, but it definitely will be by the end of your placement. It's tough getting started, but everything does pay off if you put in the work.
You'll be surprised at how rewarding a successful lesson with kindergarten or first grade feels (to be honest, it feels good with any grade). Just remember you're teaching kids, not music. That may sound weird, but it's true.
Good luck with your placement!
P.S one word of advice: Make a list of every piece of repertoire you know share it with your co-op. That's a nice way to get a head start on planning.
Thanks to Glen for sharing his words!