Basically, it is up to parents to determine their child’s readiness on a case by case basis, taking into consideration social and emotional readiness. This is not easy for parents.
A report in “Science Daily” states that “any academic edge the child gains is short-lived: Older kindergarten students scored 24 percentage points higher that their younger peers during the first few months, but the lead narrowed to just 4 percentage points by the time students were in eighth grade. Also, some parents believe that by delaying a child’s entrance into kindergarten their child will gain an advantage in academics, athletics or social settings by being older than average for his grade.
Research suggests that this is not the case and sometimes the older child will have behavioral problems.
Here are some guidelines for a child’s readiness for kindergarten.

1. Enthusiastic and Curious toward learning – eager to explore, ask questions, persistent
2. Language Skills – Communicates needs and expresses feelings
3. Ability to Listen- Follows two-step instructions , listen to story without interrupting
4. Desire to be Independent- Can be separated from parents for a day
5. Ability to Interact with Children and Adults- Able or learning to share, take turns, problem –solve
6. Strong Fine-motor Skills- Able to hold and us a pencil, cut with scissors, learning to print first name
7. Basic number and Letter Awareness-Sings or recites the alphabet, recognizes some letters and numbers, counts to ten
   Here is another check list:
   Counting:
    OnTarget- Counting to 29 -39
    Mastery- Counting to 100+
    Red Flag- Counting to 12 (How to improve-count everything and anything)

The Alphabet
 On Target-Names all capital letters and some lower case letter Names half the sounds
 Mastery -Names all capital letters and lower case letters and all sounds
 Red Flag- Names only a few capital letters and very few lower case. Names only a few sounds
(How to improve- read alphabet books every day until you child points out letters
In books, sees on food packages etc)
The Bathroom
 On Target – Is comfortable wearing his or her school clothes and operating the buttons, snaps
and zippers independently
 Mastery – Can easily operate all kinds of fasteners on clothing without assistance

 Red Flag -Needs help removing and fastening clothing using bathroom (How to improve-
Practice wearing school clothes around the house)

On a personal note, my fourth child was four (almost 5) when she entered
kindergarten. Being the fourth child, very tall, (she grew to six feet) having older siblings that taught her how to manage teasing, very social. YES she was really ready for kindergarten.
So, parents, it is your call. Know thy child “realistically”.