You asked

How can I prepare my school child for a new baby?

Talking to an older child about a new baby is certainly easier than trying to explain the idea to a toddler or preschooler. The concept is the same, however. You will want to tell your child as early as possible, and then wait for him or her to ask questions.
When your child does ask you questions, answer them as factually as you can. Preschoolers may be happy with whatever they imagine the answer to be, but older children usually want to know the truth.
Your child will probably also want to feel it when the baby moves, and you may even be able to encourage them to sing or talk to the baby in your belly. Be sure to keep whatever you discuss about your pregnancy and the baby light and positive though – you do not want to scare your child unnecessarily. With older children, it is a good idea to talk to your child about the new baby as if the baby is already a person in his or her life. Reading books or watching movies about families is another good way to start preparing your grade schooler for your new baby.
Tell your child what new babies are like, visit friends or relatives who have small babies, and look through photo albums of your child when he or she was that age.
Let your child get involved in choosing toys, clothes and other items for the new baby. Allow your child to wash and dry the baby’s clothes, and talk to him or her about how you shared your crib with your little brother or sister. You might even want to find out if your older child feels like giving any of his or her old toys to the baby.
It is not as common for older children to regress to babyish behaviour, but it does happen. Children this age will also become more anxious as the birth approaches, and it’s important that you spend a lot of time with your older children, be patient and reassure him or her that even though there’s going to be another child in your family, you still love him or her as much as ever.

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