By actual age, or by expected age had they been born at the 'correct' time?
I only ask as a medical condition that I have means that any child is likely to be born slightly early. I wouldn't want to add to any possible problems coming from prematurity by also being very much the youngest in the year.
If I were to conceive this month, EDD would be 13th September, which would be very close to the academic year cut-off if the child were to be born early.
Clearly all hypothetical, but would just be interested to know.
with thanks in advance.