And so, often against their best judgment they will begin to push those young children. Standardized tests are another factor that cause teachers to push. With all that said, I have to say that there are always exceptions to any rule. Those children may be ready. If you have questions, an experienced preschool teacher can usually give you good advice.
Some schools offer developmental assessments on request.
A child can always be moved ahead at a later date. Whatever decision you make, it is important that you feel comfortable about it, and that you stick to your guns. Other people will challenge your position which can be upsetting, uncomfortable, and start you second guessing. You don't ever have to defend your position to anyone. It might not be the right decision for everyone, but seems to be the best one for our child at this time.