Are there any novels in which the heroine crosses into a child?

Yes, many heroines have crossed into children's novels. Here are some examples:

1. "Crossing into a Boy": The heroine crossed into ancient times because of a car accident and became a little girl who was only 8 years old. She must live, study, find her place, and try to find a way back to modern times.

2. Rebirth of child bride: The heroine is a young woman who was killed and reborn on a little girl. Her family was poor and forced to sell herself into slavery. She must find a way to survive in this difficult environment and try to escape her fate.

3. Reincarnated kannika nimtragol: The heroine is an ordinary young woman who became a kannika nimtragol because of an accident. She must adapt to this new identity, deal with family problems and try to find a way back to modernity.

These novels usually have a heroine who will go to a strange environment and have to adapt to a new identity and lifestyle. These novels usually have interesting plots and lovely characters, which make readers feel relaxed and happy.