It is federal law that taking any data from children under 13 requires prior authorization from the parents/guardian. If your code takes any data, you must verify the end user's age and, if they are underage, provide a way for the parents/guardian to contact you for giving authorization.

Yes, we all know kids lie when they see the age verification, but the presence of age verification moves the liability away from the developer/publisher and onto the parents/guardian of the underage kid.

Obligatory IANAL.