I had mine done with a gun at a hairdresser at age 8. It didn't hurt at all. I was very careful about looking after them too as I had seen friends get infected ears.

I haven't set an arbitrary age for DD to get hers done. Only that she will get them done only if she wants them done as I believe it is her body so her choice. I think, depending on the child, 5.5 is plenty old enough to make that decision.