My husband was totally against getting my daughters' ears pierced until they were older, but I was torn, as I have pierced ears, love them, and find them cute on little girls as well.
However, after seeing a close friend and her 7 year old daughter go through a huge ordeal with them (infection, butterfly-back becoming embedded in the lobe, surgery with general anesthetic, over $1,000 in expenses, etc.) I now agree with my husband. All of this happened months after her piercing... not immediately afterwards. As much as my friend tried to do everything right (regular cleanings, hypoallergenic earrings, reputable ear piercer, etc.) kids really need to be old enough to take care of their ears and their own personal hygiene.
I wish you luck, but just wanted to warn you to be super diligent with cleaning and watching her ears.