My DS turns 5 in March also. He will be starting school next year and like your DD is very excited. He can write and is doing OK at it. He is still deciding if he is left or right handed so his writing is a bit messy (there are many left handers in our family!). He hasn't started reading yet but asks constantly Mummy how do you spell...." So I am spelling things out to him 1000 times a day! He has been in daycare 3 days per week for 2.5 years so slightly different situation to yours.

The decision is totally yours. I've heard that girls mature more quickly and cope better but believe me my little man is so so so ready