2. I do regret not trying to put my now 3 y.o. in the 3 y.o. class. I don't know what's covered in a 3 y.o. class and if my son knows these things already or not. He could be suddenly put in a new environment mid-year and would be away from his newly made friends.
Hi Anna, I'm no expert on this (maybe someone else will chime in) but a just turned 3 y.o. reading is really quite unusual. Like, remarkably unusual. I'm bringing this up only because I get the impression from your quote that you are considering the possibility that the 3 y.o. class curriculum might be too advanced for him. If I've misinterpreted you, I apologize. But if your son is reading books at barely 3 I don't see how there can be any question that the 3 y.o. class is more appropriate for him academically (obviously the best placement with regard to the whole child is your call).
I have a son whose birthday is 21 days past the cut off in my area. We've always had him "ahead" a year (really only 21 days) and it's allowed us to avoid a lot of difficulties.