I Grew up Like This

The day before my eighteenth birthday, my cousin, whom I hadn't seen for half a year, invited me to stay at her house, and she wanted to share a bed with me and talk all night long. I happily agreed. That night, she suddenly said: "Second sister, do you know why my mother didn't let me play with you since I was a child? Because you are not her biological child." Since then my life has been divided into two halves.