how to properly nest json data that is related

Question

I have some data which is defined with such cardinality:

1. School
1.1. Student
1.1.1 Homework

Parkside
 John Smith
  Reading assignment abc
   Score 100
  Reading assignment def
   Score 90
  Reading assignment xyz
   Score 85
 Lenny Bones
  Reading assignment 789
   Score 20

There can be many homeworks that belong to a student, and the student always rolls up to a school.

I would like to know if I am nesting my data properly in a JSON structure, or if there is a better approach.

{
 "items": {
  "Parkside": {
   "John Smith": [
    {
     "ra": "Reading assignment abc",
     "score": 100
    },
    {
     "ra": "Reading assignment def",
     "score": 90
    },
    {
     "ra": "Reading assignment xyz",
     "score": 85
    }
   ],
   "Lenny Bones": [
    {
     "ra": "Reading assignment 789",
     "score": 20
    }
   ]
  }
 }
}

I'm confused whether it is good to use value definitions as keys, or if I should design the JSON structure to always use the same key for the given attribute.