Trust me - earrings won't stop it either - if they're that stupid that they can't tell by the fact she's wearing pink, has a dress on, and bows, then they're not EVER gonna figure it out.
Personally, their wondering wouldn't bother me - if they can't work it out by the way she's dressed, then they're just too dumb in my opinion, and I won't pander any more to their inability to work it out.
If that was the only reason to do it - don't. If you have other reason, by all means, go ahead!
Remember though, even though they don't remember the pain, the younger a child is, the more risk they have of infection, considering that their immune system wouldn't be as strong as someone around 8 or so. That was part of my mother's reasoning to wait until she did. I got mine at 12.5 as I said, and the pain lasted about 3 minutes, if that. I just remember them feeling really heavy after that, and just it hurting cos I was silly, didn't do the metho trick, and got my ears infected.
Just a couple of thoughts. I would personally wait til she was about 7, just to insure her immune system was a bit stronger.
Sasch