The previous poster is wrong!! They changed the date a few years ago. The cutoff date for kindergarten for Indiana is Aug 1 but individual districts can offer early enrollment for those born in August (Sept 1 cutoff). That is still alot earlier than many other states (Oct-Dec is very common). Most schools will not bend on the Sept 1 cutoff - because state law says Sept 1 is the absolute latest, even for early entrance. I have a friend who's daughter was born on Sept 2 and no dice -- she's waiting a year. If they start making exceptions, where do they draw the line? At 2 days off? 5 days off? 3 weeks off? What's the point of a cutoff date, then? It might suck, but someone has to be the oldest, and the youngest, in the class.
You could look into a private kindergarten. Most around here stick with the same Sept 1 cutoff date but they are more likely to make exceptions for a child who is truly socially and emotionally ready (notice I didn't say academically -- kindergarten teachers care more about a child being ready socially and emotionally than academically). After a year of private kindergarten she could then enter 1st grade at your local public school.
All my kids have birthdays close to the cutoff date (on both sides of it) so I understand how it can be frustrating.