Depends on the extent of breakage and whether the tooth pulp has an exposure. As you are only 12 , all effort has to be made to avoid root canal to allow the tooth to have a proper apical closure. Depending on the extent of injury, treatment can be from a simple ceramic filling to apexogenesis procedure.
Next Steps
Consult a dentist and get an X-ray done
Health Tips
Time is very important. The sooner you take treatment after injury, the better the result. Also avoid extremes of temperature like very hot or very cold food