How should I tell my child she's going to get a sibling?
Toddlers have very little patience and even less of a concept of time, so try to wait until four to eight weeks before your due date to discuss the new baby. But if you're showing a lot and she starts asking questions, you might have to talk about it earlier.
Whenever you do tell your daughter about the baby, answer her questions briefly but honestly. Know that she may be far from thrilled about her new brother, yet with your love and understanding, your child eventually will be able to handle the change. Also avoid telling your daughter how much the new baby will need her to teach him how to swing or swim and so on. These duties may seem less fun to her than you think.