Both of my DDs were quite tired during their first year of school, however it might also depend on how much other unstructured "down time" they have. Both of my girls have had to go to after school care, which I think adds to the total load of "stimulation" that they get during the week while also reducing the amount of quiet pottering they can do, and also means that the evening home routine starts later. We didn't start DD1 on any new activities until grade 2. DD2 (currently in prep) does Little Aths, but we'll hold off on other new activities for a while