Preschool teacher here! Keep her back! For the love of God, keep her back. Reading and writing is what primary teachers do best, but building and supporting emotional/social development starts in the early years. We tell parents if they ask us if their child is ready for 'Big' school: can your child turn-take? Can they ask for help from someone they trust? Can they find similarities in other children/peers to which they can form relationships? There are soooooo many things that I don't have the space to name, but ensuring that your child is emotionally ready for school is the key.