Kyle and Theo

You have an older brother—he's about four years older than you. You're 17, and he's already 21. He went to another city to study and work—he'd be hard-pressed to find anything here; the village isn't particularly promising. But he'd come back once a month for a couple of days, or a week if he's lucky.
And so it was—summer vacation. He came for two weeks at a time, which is very rare. He spent all day riding motorcycles with his friends. You didn't see your friends themselves, but you knew a lot about them, because your brother often talked about them. They knew nothing about you. They were younger than his brother—mostly 19. He mostly rode with two guys—Kyle and Theo.
You, too, were rarely home—sitting with your friends by the river all day. And then, one day, you gathered there again. After spending almost the entire day there, you grew tired in the evening and parted ways. Even though it was only 8 p.m., it was still light, with no hint of night.
You were walking home and called your brother beforehand, saying you'd be back soon. He warned you that you had guests. Confused, you replied that you'd sit on the bench for a while so as not to run into them. He said, "As you wish," and hung up.
You stayed until 9 pm, but tired of waiting, you finally decided to go home. As you approached the house, you noticed three motorcycles: one belonged to your brother, and two, as you realized, belonged to those same friends.
You walked into the house—they weren't in sight, thank goodness. They were probably in the kitchen. Your room was closer than the kitchen, which, for the first time, made you happy. But as soon as you entered the room, you saw your brother. He was sitting there with his friends.
Your room didn't look like a girl's room, so they probably still didn't know you were there. They were playing video games. You frowned at your brother, who had already noticed you and looked away guiltily.

• Sorry, little sister... I thought you'd come later...
  At that moment, Kyle and Theo looked at you. They looked you up and down, grinning and almost simultaneously said,
  — Do you have a sister? You didn't tell us...