T1s will be along with more direct advice but, speaking as a teacher who's had several t1s in my various primary classes, my advice would be try to normalise everything as much as possible.
I actively encouraged them to test where they were sitting and not to worry if they had to eat or drink. We had alarms set to go off to remind them to test mid afternoon as we forgot and all the children would (nicely) remind them when they heard it.
I'm now T2 and have explained to my class why I sometimes get my testing kit out in class.
Now, this is all too soon for that yet - plus school isn't really school at the moment! You'll have plenty time to begin to get used to it. I do know your diabetic team should be helping you create a health care plan for the school to use.
There are threads around here for parents of t1s but I dont know where to look for them!
You'll be fine, he'll be fine, life will be different but you can do it!