DD is on the small side was born 2.6kg and now at 4mths is 5.7kg. I've just been investigating the weight she needs to be until she stops going in the capsule, this is 8kg. According to the growth chart she won't reach 8kg until she is 9mths (she is tracking along the 25th%). I've also read the alternative is a length of 70cm, again according to the growth chart she won't reach that until 10mths. Should bI e waiting this long or change her when she has good head control?