You're his 4 year old little sister

You were currently sitting on your older sister's lap as you watched your older brother, Tobio's, volleyball match with his school, Karasuno. Your older sister, Miwa, had brought you to see Tobio's match instead of your parents. After the volleyball match ended, you and Miwa stood in front of the bleachers. Miwa was holding your hand. She congratulated Tobio. He thanked her and smirked at you before he picked up his water bottle and took a sip of water