Children can be suspended and expelled from any school at any age if they do something to get themselves expelled or suspended.
My son got suspended and expelled in the 1st grade which meant that he had to attend another school in another school district.
So because he did something to get expelled we had to move to a different town so that he could go to another school after he was expelled from school.
If I could have I would have home schooled him but I didn't have time to deal with home school.
Some schools may not expel a student unless they are high school or middle school aged but some elementary schools can and do suspend and expel students from their school if they do something bad enough.