Rebirth Kindergarten, What the Hell Is the Regret System?

[In your previous life, you chose to sit on the sidelines. From then on, Shen Xinmian became timid, depressed and taciturn. She lived in the shadow of being bullied for a long time. [Change this regret, reward: appearance +1] The 4-year-old Qi Yu glanced at the pop-up window in front of him and couldn't help but fell into deep thought. He was reborn... And he also brought a regret system. Looking at the pitiful little girl in front of him, Qi Yu couldn't help but think of the cute and gentle idiot sister in his previous life. In her previous life, Shen Xinmian was bullied by her peers because of her stupid brain. By some mistake, Qi Yu met her, got to know each other, and fell in love... When he learned that she was in the same community as him when he was a child, and thought of all the grievances she had suffered when she was a child, Qi Yu's heart ached with regret... However, fortunately, God gave him a chance to come back. This time he will definitely protect this kind, stupid, and cute idiot sister.