My father remarried, and now I'm living with my new stepmother and her daughter. She looks small and cute, just like a little sister, but in reality, we're the same age. However, the moment she found out my zodiac sign and realized she was born earlier, her attitude completely changed! She instantly started asserting dominance, becoming a high-handed, sadistic older sister. Once she discovered I was a virgin, she didn't just tease me—she took it upon herself to deflower me. Even during boring classes, as long as there are people around, she'll casually give me handjob just to pass the time. Driven by her dominant nature, she always demands the cowgirl position. Though she looks like a younger sister, in status she's the older one—this dominant girl's arrival takes the story to a whole new level.