[header] How to stop being called a child [title] Examine other people's motivations. [step] When somebody calls you a child, think about why they said it. Is it your physical appearance? Did you do something that would cause them to say it? Knowing why people perceive you as a child can help you work on looking and acting more mature. 
If you can't identify a reason, ask the person politely why they called you a child. [substeps] Don't get angry with them.