Re: mom's orders?
Why go and have your belly button pierced, just so it can be taken out when your parents find out? You are wasting time and money when you know that you cannot hide it forever and it will be taken away. Once your parents find out, it will just lower their opinion of you. It shows them your lack of respect for them and their rules. They will come down harder on you than ever before. Then when you want something else, they will be less likely to allow you to do it since they cannot trust you.
Trust is everything with parents. Trust equals freedom for you. If they can trust that you respect their rules and that you yourself make good decisions, then you will have more freedom. Freedom to go places because they trust you and your judgement.
When parents cannot trust, then you cannot stay out late, go to parties, etc.
Belly button piercing is just a poser fade. Like you said everyone you know has one. Why rebel and become grounded, lose your parents trust and respect and lose your freedom just to look like all of your poser friends?