re: If your 15 year old daughter or sister wanted to get her belly button pierced

Disagree. If she is afraid to even ask you to discuss it with her bc she already knows the answer you've failed. Or if she goes and gets it anyway without you knowing and hides it from you, you've failed. Being open minded, trusting her, and her knowing that you know that a simple piercing doesn't define her values/character is a good thing.