A.P.
Hi!
Well, I wanted to share this with you. Have you ever seen Jon&Kate Plus Eight? One of the twins got their ears pierced, and that episode was very "realistic" to what happens and it made my 9 year old daughter decide to wait on hers.
There are video's online to show what happens, so she sees it. It may be something that is too intense for a 4 year old. I'm thinking of my now five year old and she saw that video and also said "NO!" to ears piercing.
I'm not trying to talk you out of it and you know that few moments of pain may be worth it to her.