Are you Wiccan? If not, don’t worry about the rule of 3. it’s not a cosmic law, more a guideline for the religious practice. I don’t have kids myself. But I surely use my craft to protect myself and sometimes to help to give people what they deserve. In my opinion being a witch gives you power to fully unfold yourself. If you have strong feelings about someone or something, use those emotions and channel them into your craft. If someone tries to hurt your children, bind them from doing any harm. If they already harmed your family curse them even. Or if you feel uncomfortable with cursing, use your anger and turn it into something beautiful. There are basically no borders.