My daughter will be 13 months old next week and she only weighs 17.6lbs. Her pediatrician has never said anything about it but the doctor and nurse at Children's Hospital yeasterday seemed pretty concerned and kept asking how much I feed her. She eats 3 big meals a day plus snacks. Lots of meat, veggies, carbs, fruits and drinks. Now I'm worried though.. She has always been a slow grower and always at the 5% for weight and height. Should I get second opinion?

Ps. She was not a preemie.