Elementary School Ontology

Yesterday was the last day of school for the shorties. The shorter was in kindergarten and the question arose whether he is now a first-grader. It was generally accepted that he now has the status of "going into first grade," but the question was whether that was a sufficient condition to be a first-grader. If he is asked "What grade are you in?", could he answer "First grade" without having yet attended a single class in first grade? Is it walking into the classroom on the first day of school or having completed all of the requirements necessary to walk in that confers the elevated status of first grader?