My Three year-old is asking to have her ears pierced.

It is easier to get them pierced when they are younger (or so I'm told). If you do decide to get them done, they may be sensitive for the first few days. As long as they are small studs, there shouldn't be a problem when they goof off together. I got my daughter's done when she was eight months and she barely ever pulled at her ears. But she figured out how to get them out of her ears. We switched to earrings for sensive ears and haven't had a problem since. She doesn't even realize they are there anymore.