Holding off Kindergarten until he is 6 *Edit

So, my DH and I decided that we will enroll our son who is almost 4 1/2 now into PreK again this September. Instead, of sending him to Kindergarten as he will just turn 5 on August 26th. I think it is the best decision holding off on the K until 2014 when he just turns 6. An extra year at the PreK will not hurt - it will only help him prepare more for K. 

Has anyone else here gone through this? Having your kiddo so close to the 'age cut off' for Kindergarten?

*Edit - I'm not holding him back from Kindergarten just because of his age. Should have mentioned that I feel he needs an extra year to work on his letters and numbers and writing his name, there at PreK. Kindergarten isn't what it used to be and you really need to know those things because getting there. At the K in my area, there is homework every night and its pretty intense as far as for 5-6 year olds. I don't want to rush him if he isn't ready and I don't think that he will be ready for K this year.