What's your secret?

I am not my parents' biological child. My family has kept this secret for 2 1 year. But by some coincidence, I knew about it myself, and my parents thought I didn't know. I first learned about it when I was in grade one. A cousin who is really far away came to my house. She married to Beijing early, and my home is in a small place in the south. When my parents went shopping, I was at home with my cousin. My cousin and I had the following conversation in small talk. Cousin: "Have you been to see your biological parents?" At that time, I looked puzzled: "biological parents?" Cousin said, "They (my parents) haven't told you yet?" I said, "No, tell me." Cousin said, "Ah … nothing." Cousin realized that she seemed to have said something wrong, and then we were silent. At that time, I was already in junior high school and began to understand. This incident planted a vague seed in my heart.