Yes

Girls tend to grow at a faster rate and their puberty also starts a lot earlier than boys. This could be understood why girls ted to be a lot more mature than boys. However boys tend to be taller than girls because of the extra childhood they have than girls. As soon as a girl mestruates, she has become a women sexually, but mentally, well I reckon there's no match.

There is a school near us that is separating girls and boys in the younger grades. They develop differently and apparently it can make a difference is how they learn. Seems like you might have to trade some socializing skills for the learning ones though. I thought it was interesting anyway...