First ask what gender expectations are in your society
We only consider behaviour "gender non-conforming" if there are more-or-less-rigid conventions for how each gender should behave. This is where the whole "gender as a social construct" argument comes from.
Consider hair as a simple example. Men in Western Europe (and then in the USA) had a tradition of men cutting their hair short - to quote Bob Seger, "all the same old cliches, is that a woman or a man". But Sioux and Blackfoot men only cut their hair to express grief; Chinese culture had a tradition of not cutting their hair because it was seen as disrespectful to their parents; and for Rastafarians it is a tenet of their faith.
More significantly though, what jobs are traditionally carried out by men or women? In the USA and Europe, farmers tend to be men. In many South American and African tribes though, farming is a woman's job; men are hunters or herders. Childcare is usually led by women, but there are tribes where this is not the case. Western medicine has a strange division between overwhelmingly-male doctors and overwhelmingly-female nurses. Even more strangely, some highly physical aspects of medicine such as physiotherapy are overwhelmingly female, even though they have never formed part of the "caring-for-the-sick" role that tended to make nursing female-dominated.
And then there's cooking. In the UK it always used to be seen as women's work, to the extent that my all-boys school did not even consider offering cookery lessons until well into the 1990s, and then only because it merged with another school. And yet France has always had a long tradition of male chefs, and that tradition meant that most commercial kitchens in the UK were run by men, even at a time when schools actively refused to teach boys how to cook. That's an example of a society not even being internally consistent with gender expectations.
It goes back further than that though. There is substantial well-documented research that gender expectations are imposed from before a child is even aware of them. From birth, girls are overwhelmingly praised for how they look and how well they behave; and boys are praised for carrying out activities. Toys and clothes are gender-differentiated from birth too.
Gender non-conforming doesn't necessarily mean a girl wants to be a boy, physically or sexually. It can just as much be that a girl wants the opportunities which boys have and which are denied to her. Fewer activities are denied to boys, but they do still exist - male nurses and physiotherapists are still rare, primary-school teaching is overwhelmingly female, and it's virtually impossible to run a preschool simply because parents won't take their children to you.
If you've just blindly assumed that your society has the same gender roles as 19th-century Europe, you're probably not in a strong position to write gender. Clothing is a fairly superficial aspect compared to everything else.