From the age of 16 and up.
Piercings for anyone under 16 are allowed only with the consent of a parent or legal guardian.
Quote from the law:
“In a business that, in whole or in part, performs body piercings for the purpose of wearing jewelry, no person shall pierce the body of a minor under the age of 16, other than in the earlobes, unless consent has been given by one of the minor’s parents or legal guardian.”