I got my bellybutton pierced when I was 16 (I am now 22). I had done a lot of research on the subject before I did it and before bugging my mom, I had found a shop that would pierce me with her consent AND used only brand new needles for each piercing. The piercer was also in the profession for over 20 years. I had to prove to my mother I knew what I was getting myself into. The piercing also has to be taken care of afterward. It's not like it's pierced and you are done. It takes time to heal, you HAVE TO follow the aftercare instructions the piercer gives you. If you think she is responsible enough then let her.

Personally, my bullybutton piercing didn't at all, the clamps pinched a little. I didn't feel the needle go in. I did get it caught on my pants once and it hurt a little.