I'm a dad of 3 yr old girl. My daughter started asking questions about lipsticks and eyebrows, of course influenced by her mother, but for me make ups are a big NO NO. but if she reach the legal age and started living on her own. It will be her choice though. As long she is living in my house, it will be my rules.
I see flower girls wearing make-up so I'd say 7 or 8. I will make sure first that she's not allergic into something.