I've often wondered about the value of the "levels" assigned by those academic tests. I was pulled out of my 2nd grade classroom and subjected to tests for days. The tester rated my verbal and language skills at 7th grade level. I'm not sure whether to take that as a compliment or a warning about the validity of the testing.
I knew a 5-year-old who had been through 3rd grade in a Montessori school whose parents chose to enroll her in public school kindergarden because they were concerned about her social skills. She loved it; the other kids loved her and the teacher said she was better than having an aide in her class.She read "Little Women" in KG.
BTW, she never complained about being "bored."