I have also confused someone's sex because of their haircut, maybe because they don't wear earrings, also with a topless long-haired boy (the reason is because he can be bare-chested) I remembered another movie where a group of children undress but they realize that this child is different (because of his reproductive system) they made fun of her.
I liked that scene in the lighthouse, and the kiss they shared except for the radio call that ruined the moment.