There is really no general answer to your question because of the fact that chronological age is not the only variable to consider. But, as a rule, a child who has turned five and is developing in an entirley normal fashion should be perfectly 'ready' to be in kindergarten and you would not be making a mistake by planning for her to do so. The exception to this occurs when a child has just turned five and is also very immature or displays some delay in development, but that is not the case with your daughter.
I think it would depend on her personality and if she is socially ready. If you feel she is ready go for it. I was that way with having my birthday in july and being one of the youngest in class--the only drawback that I can see is shen she gets older and graduates she may not be able to get some summer jobs with having to be 18 first--but that is a long ways off.
Two of my children have birthdays in August. My daughters is on the 26th and my sons is on the 10th. I held them both back and waited until they were 6. My daughter could have gone when she was 5. She is very social and one of the smartest in her class. My son got started at the right time. His personality is different and he is not very social. I think it depends on the kids personality. My thought was: I didn't want to start them too early and then have them held back. I thought it was better to wait.