Usually with a nutrient deficiency a number of nails would be distorted. At 12 years old, you
need to eat 2200-2000 calories per day and have a variety of food that includes starches, meats, fruit and vegetables. The fresher the fruits and vegetables, the better nutritional value. If your mother is concerned, suggest going to your MD and getting your blood tested. It will indicate if any nutrient, vitamin or mineral is deficient or not. Thank you for your question.