I have a few piercings and I would never have anything done with a gun now, especially by a 16 year old shop assistant in a high street shop. I know they're most likely sterile and safe, but if my daughter wanted to have her ears pierced, I'd go to either an established piercer (will use a needle, much safer than a gun, and not any more painful), or a nice jewellery store. Only my opinion though! I had my ears pierced as a toddler with a gun, and had no problem with it, so it's up to you, really.