My daughter is on the small side too for 7 months - she is 15 lbs and 25 and 3/4 inches long. If the Dr didn't seem concerned about her weight - I wouldn't stess over it. As long as she is healthy that is all that matters. The height and weight charts are just an idea of where they should be. My son was always at the 25th percentile up unil he turned 2. He was in the 90th for height and 75th for weight. She may catch up later and if she doesn't it isn't that big of a deal if she's a little small. It's cute for girls to be petite.