The vow that won't be forgotten

Morning sunlight crept through the thin curtains, painting pale lines across the concrete floor.
Shiromi was already awake, sitting cross-legged in the middle of her cramped room. Around her were weights, resistance bands, and a worn punching bag stuffed with old rags.
To anyone else, this would look like a prison cell. To her, it was the forge where she had rebuilt herself.
She closed her eyes, feeling the dull ache in her arms and shoulders. Yesterday's training had left her muscles screaming, but she welcomed the pain. Pain meant she was alive. It meant she was moving forward.
"Another day," she whispered to herself. Her voice was flat. "I need to be more stronger."
She could still hear her mother’s voice—Run, my precious! Run! Don’t look back!—echoing in the quiet morning. She pressed her palm over her heart and felt its steady, relentless beat.
"I won’t stop until you’re avenged!"
She dressed in her school uniform and tied her white hair into a short ponytail. In the mirror, she looked almost ordinary if you didn’t see the way the fabric strained against her arms or the faint scars along her collarbone.
The world only saw a little girl in a uniform. That was fine. Let them underestimate her.
She picked up her bag and stepped out into the morning air. The street was quiet. A delivery truck rumbled past. A cat darted across the sidewalk. All so normal. All so peaceful as ever. "If only that day was like this then..."
She walked past the burned-out foundation of her old house, hidden behind a tall construction fence. She paused, touching the fence lightly.
"I haven’t forgotten."
Then she kept walking.
At the end of the block, the new transfer student was waiting at the crossing—dark hair, clean uniform, waiting to cross the road. 
For a moment, she was reminded that he was the first person to ever dared to get along well with her like treating others.
"...whatever."
"Hey~ Is that you? Good morning! Shall we walk to school together?" The boy seemed to saw her, waved and greeted her just like treating her as a friend. 
But she didn’t look at him. As if he wasn't there at all. She walked past without a word.

"Hmm, maybe she didn't saw and heard me." The boy crossed the road and continued his way to school. Even though she didn't reply back, he didn't mind because in his heart he already knew how would the girl responded back. "Nevermind, we'll see each other at school after all."

Meanwhile, as she turned the corner, her heart kept beating faster, and she hated that more than anything. "What's wrong with him? What does he want? Why is he being so nice to me?" Thoughts surge, even a girl that been through hard times would be moved by kindness. But the vow that been carved will not be forgotten before her goal would be fulfilled. "Must not be soft, must be strong."