Not many respectable professions reveal their navels, thus a belly button piercing is acceptable in several ways. Most respectable professions frown on piercings, other than ears, and this can hold you back from making money in your future.

Your parents' house, their rules. You have 2 years before you can move out and do whatever you want with your body, but remember that whatever you do might actually end up holding you back from a good career.