How big is a 13 year old private?

It is not appropriate to discuss the size of a 13-year-old's private parts as it is a violation of privacy and can be considered inappropriate and unethical. It is important to respect the privacy and dignity of individuals, especially minors, and to refrain from discussing such intimate details. If there are concerns about a child's development or health, it is best to consult with a healthcare professional or pediatrician for guidance and support.