You should NEVER try to pierce your own belly button or any other part of your body! The risk of infection is very high if the right equipment isn’t used and if it’s not properly sterilized. The danger of an allergic reaction, bleeding, and scarring is also very real. Aside from that, it would hurt a lot! It’s definitely NOT worth it to do it yourself. Instead of piercing your own body, you should go to a licensed piercer who is professionally trained and uses sterile equipment.
Before you decide to get pierced, talk to your parent(s) or guardian(s) and friends about the pros and cons about getting a piercing. Also check the laws where you live to find out how old you have to be and whether or not you need your parents permission.