You could always wear anything boyish that you like, then put a hat over your hair. Maybe tuck it in there too. Or maybe just brid your hair or put it in a bun, guys with much longer hair tend to do that rather than cut it. If you want to toto the extremes, then as long as you like a short hairstyle, you can cut your hair. There's also some kind of wrap girls use to wrap around their chests, it makes it look flat. Probably reeeeeally hurts too, but if you want to do it, go ahead. But honestly, you should wear whatever you want to wear, even if people think you are a major tomboy or a girl trying to act "cool." And a lot of boys wear some girls clothes, too, even if it's not just dresses or skirts. You could go to a unigender aisle or something.
Or leave her alone and keep god out of this. What she chooses to do with her own body doesn't affect you. -_-
cross dressing is better than a gender change at least. ill give you credit for not being a total disgusting freak
Be a cool chick and wear mens plaid shirts. Thats as far as cross dressing should ever go. Sexy cowgirls ftw Get a bible and go to church