We would need a little more information. What type of dog, how old is she, how long have you had her, what happened earlier that day and that week with both your dog and between your dog and your mom's dogs, is it possible your dog is ill or injured?
Edited to add: I know even severely dog aggressive dogs can be wonderful with people. My last dog never so much as growled at a human in the 12 years I had him, but he would have killed every dog on the planet if he could have. So don't worry that your dog will be dangerous with people even if she's dangerous to other dogs.