H.
I am a preschool/kindergarten teacher and I have a little one with a Sept 11 birthday - so I can answer from teacher and parent perspective....
The age requirements are set by each school district and most in this area are Aug 31st/Sept 1st. That means children need to be 5 before that date to begin kindergarten. The preschools typically work back from that so many programs follow that same deadline for children entering 3 or 4 year old preschool programs. There are some programs that either follow different cut-offs or have additional classes to catch those kids that just miss the traditional cut-off. These programs often have 3's, 4's and pre-k classes. Should your child begin preschool when she is still 2, she will end up having 3 years of preschool/pre-k unless your school district has a late deadline or is extremely lenient to let her begin kindergarten early.
My daughter is in her second year at St Paul's Preschool in the North Hills. It's a wonderful program and does allow for those late birthday kids by having a class for younger and older students and also a pre-k class for those 4 year olds that are not eligible for kindergarten. It is a nationally accreditted program. They do have a 2 day (half-day) program for young 3 year olds. If this is in your area, I'd be happy to pass along any info to you.
As a parent, it may seem pretty silly to have to make your child wait another whole year before beginning school. Often girls can seem more mature or a child might be reading early or have strong academic skills and a couple months doesn't seem like a lot. The reality is that it is my experience from having taught children that were past the opfficial cut-off or were late summer birthdays, there is a difference when in a group with the older kids. In so many ways tehy end up standing out as the babies in the class. Sometimes they stand out academically other times it is social development where they lag behind. They just don't tend to be as well rounded as the older children. As a parent of a child with one of those late birthdays, I try to remind myself that it is a gift because I get to have her at home with me that much longer before having to start into the many many years of school. She will be the first one getting her driver's license and will get to be a leader because she had more time to grow in confidence than if I had pushed her ahead. While teaching I never saw an incidence where waiting and following the age guidelines put the child at a disadvantage. There were plenty of children that had various problems because they were pushed along too early though.
The curriculum is getting pushed lower and lower so more and more is expected at a younger age. By letting your daughter be an older child in the class, she'll still be challenged. Also, many parents of summer kids either elect to have their child wait to have extra growing time or preschool teachers suggest it. So, your daughter would not be the youngest in her class.
If you have other questions or concerns, please feel free to ask. Or if you want any preschool info...