I have a question, if you don't mind? When is your sons birthday? So when is the cut off date? How will your son be the youngest in his class? I am just curious, because I am from Ontario Canada, so it is a bit different. Here we have junior (JK-like a 'transition' class...) and senior kindergarten (SK) and my DS started JK when he was 3 almost 4 because his birthday is not till November.... But then again JK and SK are just 1/2 day everyday... And he will start grade one this fall when he is 5, not quite 6. Now he is ready for grade one because he can read, and write very well already, so that does not worry me. Just wondering how this works for you?
Here (TX), you must be 5 on or before Sept. 1 to start K. K is optional; you can start your child at 1st grade. To start first grade, you must be 6 on or before Sept. 1. You must enroll your child by 7 years old in school, unless homeschooling. You can not start with second grade, you must start with first. So in a nutshell, you can start your child at age 5 or 6 in K or skip K. You can start your child at age 6 or 7 in first grade. Age is based on your age of Sept. 1. K, like first, is full day, 5 days a week.
It is recommended before they start K that they know their letters and sounds, numbers, can count to at least 20, are able to recognize their first and last name, are able to write their letters and first name, and know their address and phone number. They also need to be able to sit still and concentrate for at least 15 minutes and be able to keep their hands to themselves. They should also be past needing a nap during the day so that they can be going as strong at 3 PM as they were at 8:00 AM (the school day). By the end of K they are doing simple addition and subtraction and reading. They'll also be able to recognize the parts of a story--beginning, middle and end in addition to author, narrator, climax, etc.
Preschool is not required and there are no rules governing it. Generally, in my area you can do toddlers (anywhere from 12-18 months, depending on the school), twos, three, pre-k and transition (5 year olds starting K at the second opportunity or for those skipping K). Transition classes tend to be what the first semester of K is over the entire year. That is why those that do transition tend to be at the top of the grade in K, and very bored the first semester if they aren't put into a group of advanced kids. These kids tend to be put into the GT (gifted & talented) classes; not so much because they're brighter, but their learning is ahead.
This tends to carry on through elementary school. There tends to be some evening out in junior high/middle school and high school. Although these kids tend to stay ahead by nature of having had the material in advance. Lots of people start holding their kids with May birthdays to give them that edge. And of course, lots of people hold the late summer birthdays because of size or maturity. Of course, this can vary from area to area.
School starts in TX no earlier than the last week of August, by state law. DS#3 birthday is September 1. He would start at 4, just prior to his 5th birthday or at 5, just prior to his 6th birthday. If he went the first time he was eligible, there is no way anyone could be older. And I know if he went the second time, there will be several kids already 6. I really think sending him at 5 would be better, but I don't know. DS#1 is gifted (math & science) and I see a lot of similarities between the two--although that means nothing. I just know with DS#1, had he had DS#3 birthday, it would have been better to send him earlier.
This is a decision that needs to be made early around here. Preschool registration starts in January prior to the upcoming school year and not every preschool offers transition, or transition classes of equal value. Some transition classes are half day, others full day, and can be anywhere from 2-5 days per week. If you need to research schools, it can take awhile. Plus, there are large non-refundable fees associated with registering. And if you register without intent, you are taking that spot away from someone else; of course, there are always wait lists, but that means losing money put down at another school that has room.