Don't worry. I know you'll be fine since you're a good teacher.
I also experienced to teach Grade 1 students and it wasn't easy at first. I thought of quitting during the first week. Good thing I was able to force myself to give it a try for another week.
Fortunately, I was able to cope with the activities as well as their behavior. I handled a class of 30 kids. I still can't imagine the chaos I experienced every day.
But, I survived and now I realized how fulfilling it is to teach those young angels.