I don't personally agree much with redshirting, but only because most I know who have done it were because they wanted their kids to be larger/more coordinated when they get into sports in late elementary.
Kindergarten isn't required here, and nowadays, unfortunately, is generally full day.
I wished I'd been put in school earlier; it was boring enough. But I'm grateful I wasn't diagnosed until my late twenties (with Asperger's under the DSM IV).