I think agency is meaningful as a mode of thinking and taking action. If we don't take responsibility for our own choices, what do we have left? To me that seems a more relevant aspect of courage.
I also think there's room for both agency and thinking about how modern cultural forms of gender have affected people. Most choices are derived from culture, ranging from the idea of eating cereal and milk for breakfast, or the massive popularity of blue jeans, or removing hair from the body on a gender-differentiated basis. But out of the virtually infinite cultural trends that exist, we adopt some of them for ourselves, and not others. And out of the ones we adopt, we should critically examine ourselves to see whether we do it because we like it, or because we feel pressured to.
If choice is not a major variable, and we merely respond to society, then I would expect that the outcome is that we follow all typical norms rather than just some subset of them. Because if we follow some and not others, wouldn't that imply personal preference or choice?
I started removing hair in my early teens too, about the time it is common to do so. But that's around the same time girls often start wearing makeup, and I decided not to. Aside from occasionally dabbling in it as a novelty, it doesn't interest me. I still don't wear makeup from day to day. So clearly, it was more than just following trends. Some trends I agreed with and adopted, and others I didn't and went against the norm. The idea of removing body hair from some areas appealed to me, because it felt and looked appealing in my view, and still does, and I can use longer term methods to keep it simple. The idea of painting my face every day, then removing it, seemed more like a hassle that I didn't want to participate in, so I didn't. I enjoy being able to roll out of bed and pretty much go straight to work.
I would agree that it's terrible for young girls to be shamed into conforming to societal fads. Especially when it's very specific shaming, like when parents or friends or early dating partners pressure them into changing for society. But at the same time, I don't assume every single time that simply because someone's preferences happen to align with common behavior, that they do it because they are pressured to. They might simply like it, have noticed the trend, assessed it, and adopted it, while not adopting others.