Children start to express their own opinions around two years of age, so you should involve your child in decision making as soon as they are able. Ask them how they feel about talking to other people about them being intersex. Remind them that there is nothing to be ashamed of, but you want to make sure that, when they feel ready to tell others, they understand what kind of reactions they might get and how to deal with them.
It’s also important to discuss who else can tell people, who they can tell and how this is done. Any personal information about a child or young person should be managed carefully, with them always feeling in control of who knows and when. It’s also useful to discuss terms and language to agree on what words are used and how it is explained to others.
Please also keep in mind that your child might think differently about the subject during different stages of their life and that this conversation should be revisited at all significant milestones (starting a new school, moving to a new neighborhood/city, joining a new group/club).