K.G.
Whatever age you decide to get them done, please be sure to have a professional piercer do it...do not let someone use a piercing gun.... they can not be cleaned properly after each use and that is what can cause the infections.... the guns can not be cleaned and sanitized properly because of all the little pieces and grooves in them.... they are used on every person that comes in to have their piercings done, just a new set of ear rings are put into it each time. If the person being done before you come in happens to bleed, it gets into the gun and then the germs get into you when you have your piercing done.
Go to a piercer who uses a hollow needle to do it. They will use a brand new needle each time and the earring is put in the end of the needle and put through as the needle goes through the hole.
Then you should use antimicrobial cleanser on it everyday and follow with warm water with sea salt to help it heal. This also prevents infection.
Most piercers will use surgical steel posts because you are less likely to have an allergic reaction to it.
If you decide to get hers done soon, make sure you are willing to clean them and take care of them for her everyday. You will probably also have to keep reminding her to not touch them as that will also lead to infection from germs being on her hands.