H.J.
E.- Good luck with your choice. My personal opinion is that children will learn whatever you teach them. I have a 6 year old who reads at a 3rd grade level. She has been in a preschool learning enviornment since she was born but, never a Montessori or a private school. I think Montessori has it's place but, not all enviornments are right for all children. If your child is doing well where she is-I would leave it be. Stability and comfort really help the learning process. Please let me know if you have any other questions and I'll see if I can help- I have been a preschool teacher for 15 years.
Good luck-H.