For most of my life I was just Willem Reerink, the half-Dutch kid with the funny spelling of “William.” This background wasn’t interesting to my classmates.

However, this changed one day during A.P. Economics. Toward the end of class, our teacher said we could start our homework. As I took out my workbook, others began discussing who in our class resembled basketball stars. One pointed out that nobody looked like any African American players. Why? Well, because there weren’t any African Americans in our class.

Puzzled, I slowly raised my hand. “I am,” I said.

The whole room went silent. Everyone’s eyes were on me. Even our teacher looked surprised. I guess my caramel skin hadn’t attracted attention before. Our town is close to the beach, and everyone has a deep tan.

Then the silence changed, and I was bombarded with questions about which side of my family and exactly what percentage of my heritage was black. Many wouldn’t believe my mother was African American and had to verify my claims on Facebook. Pictures of my African American family at a big reunion in South Carolina soon quieted any doubters.

As the truth set in, I immediately sensed my classmates saw me differently. I think they felt betrayed. “Willem, how come you never told us?” they asked, like I had hidden some tragic secret.

Soon the whole school was buzzing: “Willem’s black!” I got fist bumps from guys I’d never spoken to and questions about rappers I’d never heard of. One kid told me I wasn’t “really black” because I swim and don’t play basketball. I was the only black student taking A.P. classes; the other two African American guys didn’t have great grades and even got into a fight with each other (one got suspended and the other expelled). And so I became “the smart black kid.” The kid, my classmates said, who would automatically get accepted by any college just because he’s African American.

I felt sad at first. I had earned some cool points by being black. Yet I also felt as if I’d dropped in my classmates’ esteem. I had worked so hard to be a good student and athlete, but my achievements didn’t seem to matter anymore, only my blackness did. And I felt really trapped by stereotypes for the first time.

For me and my family, being African-American always meant a history of community, struggle, and hope. Collard greens and cornbread are staples at holiday meals. My great-grandfather was in a segregated medical unit in World War II, and later became a medic for the LA Dodgers. “Pops” sounded just like Nat King Cole when he sang. My mother was told to “go back to Africa, N—r,” when she was in school. She instead went on to be the first in her family to earn a master's degree.

Now I started to understand how hard it must have been for them to pursue their potential in the face of others’ preconceived ideas of who they were.

I realized I could never go back to being just Willem — either to my classmates or myself — and that was OK. I decided to become a role model instead. I want my classmates to know black students are as diverse and ambitious in their goals as anyone else. We can be basketball stars, earn great grades in A.P. classes, or do both. I’ve also worked harder to give back to those not as fortunate as I am. I want to show the underprivileged kids I teach at the YMCA pool that they, too, have options. I hope they’ll see it’s cool to be smart, to strive, and to lead.

That day in A.P. Economics changed people’s perception of me — and it changed my perception of myself. That day, I became black.