
Too late!
The first problem you have is that you're already too late! You need to get to the young girls when they start school, ideally before at kindergarten age, teach them as early as possible that tech and STEM in general doesn't care if you're a girl or a boy.
The problem is that even by kindergarten age the "damage" is already done, boys and girls have already been brainwashed into gender roles. Now don't get me wrong, nothing wrong with gender roles but as my wife was told way too many times growing up, "What the hell do you want to learn about computers for?! They're for boys to play with!", so she grew up like most young girls and ended up in a teaching role in a nursery school. I met my wife when she was 16 and I've encouraged her these last 30 years to enjoy tech, use it and do whatever you want to do and I'll support you, since then she now handles all our extended family IT support matters!