Ah yes, welcome to the world of school!
The stealth late start for younger children is just the first of a long line of things that will remind you (should you have forgotten) that while nurseries exist for the convenience of parents, schools most definitely do not.
Waiting in the wings to drive this point home are:
The secret INSET day, which you will find out about at 3.30pm on Friday for the following Monday.
The nursery assembly, which will happen at some inconvenient mid-morning time, like 10.30 on a Wednesday. You won't hear about it till 3.30pm on the Monday.
The undercover dressing-up occasion, in the guise of World Book Day/Assembly (see above)/ or nursery Nativity/Christmas play. You will get a maximum of 48 hours notice that your child will require a costume involving either 15 hours at a sewing machine and/or some incredibly obscure, out of season garment, such as green tights, or a purple poloneck that will have you posting desperate, panicky pleas on Mumsnet.
The school outing requiring a packed lunch and (usually) financial contribution, which they will inform you of via note sent home in your child's bookbag. You will find this note at 7.30pm the night before the day in question, squashed under a tetrapak of out-of-date milk and a couple of uncompleted homework sheets.
The school fair, requiring you to (usually) bake cakes, though other contributions will also be required. You will get approximately 24 hours less notice than you need to procure/make requested items without having to stay up till 1.30am or make late-night trips to Costcutter.
Ah yes, so many happy days to come.