The medical science says to take 2 precautions.

1. Make her wear the best helmet, including face mask, that you can find. The helmet is to reduce impact forces from a fall to the ice or impact with the boards.
2. Do not let her play in a league that allows any body checking at all until she is 14 years old.

14 years old is when the brain tissue is finally properly protected with myelin. Unfortunately, girls in the young teens have the most struggles with prolonged concussion symptoms. If you can convince a girls league to ban all body checks even during the older ages, it will make for some exciting skating and stick skill hockey.

There are rugby leagues that are becoming "Touch rugby" leagues.

There are some who are trying to stop heading the ball in soccer, especially younger than 14.

Hopefully, as she gets older, the leagues will become more concerned about head injuries.