My daughter is 5 with a late November birthday.  She attends a Montessori school and has spent this year in the equivalent of a kindergarten classroom.  Now we are switching to public school and have to decide whether to send her to kindergarten or first grade.  Everyone who has met her, including her current teacher, comments on how mature she is, so I don't worry about that.  Academically, I'm not as certain - Montessori is different than traditional school so although she does fine there, I worry that she might struggle in first grade...she can read basic words but is by no means reading well.  She can count and do basic addition (e.g., 5+3=8) and can write notes to us and has a robust vocabulary.  She's above-average in height, is incredibly well-mannered and is appropriately social.  Her best friend is also entering first grade (is currently in KG at the school they'll attend) as a legitimate 6 year old.  I was also young for my class (September bday) and did fine, but I guess I wonder whether she might become more of a leader or excel if we waited another year for first grade, and I know it's tough to be the last kid to get your driver's license or be playing sports with kids in the class behind you (in city leagues that go by age, not grade).  Also, she has two younger brothers and this would make her likely 4 years apart from her brother (he has a Sept bday and I assume we'll wait to send him) who is less than 3 years younger.  Any advice?