She refused and she even argued that two of her friends used to be topless at home also and one of them had also started to grow breasts.
In a way we were driven by both our boys who both started to look at her in a different and definitely interested way. Well, to be precise, we didn't ask her right away when her breasts first budded but only a few months later when they started to really develop. We know this problem! We too had let our daughter go topless at home when she was a child and she didn't understand we asked her to start to wear a t-shirt once she started to develop breasts.