Can you get your belly pierced the US at 12 years old?

As far as I know, across the US it is 16 with parent/guarding consent or at 18 without parent/guarding. That goes for any piercings, except ear lobes which can be done with a gun and that is the only piercing that should be done with a gun. But you'd still need parental consent.

I live in San Diego, California and I had my bellybutton pierced at the age of thirteen. It is absolutely required to have a parent with you, and they will usually ask you for an ID. A school ID is what I used, just to make sure I was really my mother's daughter.