The age at which different people become interested in the opposite sex. It's different. As early as ten years old. Maybe 17, 8 years old. Generally speaking, it should be about 12 or 3 years old, which is the initial stage of sexual development. Because hormones in the body begin to secrete, that is, sexual development begins, the most direct thing is to start to react differently to the opposite sex. At first, the two sides hated each other, from the first two small conjectures to the natural separation, boys and boys together, girls and girls together.