"The Kind of Light that Shines in Texas" is a short story by Reginald McKnight about a child's perception of race relations in the 1960s.

The narrator is Clint, a middle-school African-American child in a predominantly-white classroom. Despite his efforts to be accepted (invisible regarding his race) he is frustrated by his teacher, who tells racist jokes, and the presence of two other black children who he believes to be dragging him down. Despite his own heritage and skin color, Clint is racist himself, and it takes a severe shock to change his mind.

Clint is twelve years old when the story is told. He notes that Marvin, who is one of the other black children in the class, is "at least two grades behind," making Marvin likely fourteen, and that Ah-So, the silent black girl, is "close to sixteen."

You couldn’t expect me to know anything about Texan educational practices of the 1960s, so I never knew why there were so many older kids in my sixth-grade class. After all, I was just a boy and had transferred into the school around midyear.
[...]
Yet though I was only twelve then...
(McKnight, "The Kind of Light that Shines in Texas")

Clint notes that his actions during the story, especially his attempts to get the other students to like him, are based in his underlying assumption that they all associate him with negative qualities based solely on skin color. He knows this, and yet believes the same things, being ashamed of Marvin and associating himself to those negatives regardless of what others think. A lot of his thoughts are based in his dissociation from community, not having friends and family close for support, as well as the well-meaning but not-followed-through intermixing of races during this less-enlightened era. Clint assumes that animosity is based purely in skin color, and while that is partially true, he fails to recognize that the animosity of his teacher and a school bully is also based in his own vulnerability. Clint is singled out more for his desperation to be accepted and to discard his heritage than for his skin color.

How old is the narrator in "The Kind of Light that Shines on Texas"?

In the short story "The Kind of Light that Shines on Texas," author Reginald McKnight does not disclose the actual age of his narrator Clint for a number of paragraphs. Prior to that, we learn that Clint is attending an integrated primary school in Waco, Texas. Primary school is another term for elementary school. We also learn that there are a surprising number of kids who are well past elementary school age in Clint's 6th grade class. For example, Clint reports in his narration that the third African-American kid in his class, the girl nicknamed Ah-so is actually 16 years old. Clint further reports that "there were at least half a dozen older kids in" his class and that one kid named Lawrence Ridderbeck was rumored to have a "kid and a wife" (p. 2).

However, before the reader can begin speculating that our narrator Clint is also well past the typical age of 6th graders, by the time we reach about the 7th paragraph in the short story, the reader learns that Clint himself is only 12, just like other 6th graders are commonly between the ages of 11 and 12.