DD has just turned eight. She reports being the smallest in her class and I assumed it was because she was the youngest too but I've just looked at growth charts and she is in the 25th centile for height and weight. In itself of course that's not a problem but when she was born, she was about 80th centile so she has dropped quite a way. DH and me are both relatively tall and DS, 2.5 years younger, is in the 91st. Is it something to worry about?