Hi, grinding in children can be due to various factors like nutritional deficiency, worm infections, stress or looking at her age it could be due to her permanent teeth erupting. It can also be due to improper contact between upper and lower teeth.
Next Steps
Consult a dentist if you see wear of teeth. Temporary crowns/ night guard can be a solution to this.
Health Tips
Try muscle relaxation techniques at home. Add salads, fruits, nuts and seasonal veggies in her diet and keep her hydrated at all the times.