My daughter is late August born. I think the January intake disadvantages them even more - older children have more intense teacher:pupil ratio for four months which puts them even further ahead. If you have the option (even though it's counter- intuitive) I'd put them in in September. I agree with gwod that relationships are formed early on and it's difficult for a late starter to find their feet. My daughter was subjected to some rotten bullying when she joined a new school in year one as the queen bees were already firmly established.