What is a reasonable age to get a belly button piercing?

maybe from 15 but i got mine done on the 31st December 2012 when i was the age of 14, despite being 14 though i was 15 in January 20th 2013 so it was not bad but it does hurt a bit but my belly button piercing is infected and has been since i got it pierced and it kills to take the belly bar out and put it back in. however the belly bars you can get some cheap but just a few other than that they are like 12 or 10/ even more pounds so yeah not very cheap