I think babies having their ears pierced seems to be a lot more common in other countries than it is in Britain.
Like hayley90 said, I also find earrings uncomfortable to sleep on so I'd not want Daisy to have to feel uncomfotable but not be able to express it which is another reason why I'd wait a good few years.
I think it is a lot more popular in the states, and in some southern european countries, and africa. I think it used to be really popular over here in the UK too.