I wouldn't sweat it. My daughter, at 11, was a couple of inches shorter than yours, and weighed 89lbs. Now that she is 14, she is 5'3" tall, and weighs 112. She is a beautiful size. Softball and cheerleading have had lots to do with this. With your daughter playing basketball and eating healthy food, I think you will be in the same situation I am in a few years. Keep an eye on her, and if you or her doctor get worried, then address it. But until then, I think she is right on track.