On the topic of delaying school for a year, this is pretty much only in the US where some parents will hold their children back from Kindergarten (when real school starts for them) to give their kids an advantage especially for sports. This is called red-shirting. The month cut-off is not standardized throughout the country. Some states have december as the cut-off and some august and some september. Where we live, it's semtember first.
They usually only hold summer birthdays back. So if the cut-off is September 1st, the august, july, june and even some may and april kids might be held back by their parents. It's usually boys who are held back too.
This will not happen in Singapore because parents send their kids to primary one based on the year they are born and you can't not send your child to primary school when they are supposed to.
I see a big difference physically and socially with the older kids who will be in the same school year as my May baby. Academically, he seems to be more advanced than everyone else, even the older 4 year olds in his class. I will not be holding him back at all. I know people who held their children back though. One of the kids in his Sports Skills class at the Little Gym is a redshirted kid who will be entering Kindergarten at the same time as my son. I don't see a huge difference between my son and this kid except that my son can read and this kid still can't.
That said, I was extremely relieved when Ian was born in October since he will be one of the oldest in class.
Now to answer some questions. I'm in Texas. Not very exciting I'm afraid. My trip home to Singapore is determined by my da4 er zi's school and sports schedule. It depends on whether he does the summer swimming league.