"You can do all that and be a girl," Gideon countered. They'd probably missed the boat on getting her a proper foundation in etiquette and fashion, anyway, even if she wanted to get into all of that stuff. For one thing, Gideon didn't know what all that stuff would even entail; he'd certainly never been interested in it and he hadn't had a serious relationship with a woman who was. He'd never gotten much beyond flirting with a woman of his own social status. Even if he did have the knowledge or resources to connect her to that world, though, he wasn't sure it would do any good. Just look at the Scrimgeour girl who had been raised in a Muggle slum until she got her Hogwarts letter; her parents had been able to give her every advantage from the age of eleven onward, and she'd ended up (from what he could tell from the rumor mill, anyway) disgraced and estranged from society, and who even knew what she was doing now. He certainly didn't want anything like that to happen to Billie — so perhaps it was for the best if they avoided the angle of trying to be a respectable young woman altogether.

"There's a whole Quidditch team of women, you know," he pointed out. "And you could still do plenty of interesting things." Probably not fighting, admittedly; that wasn't really appropriate behavior for men to be engaging in any more than periodically, and would doubtless raise eyebrows for a woman... but hopefully it was also the sort of interest she would grow out of.

Which was really the crux of the matter. If Gideon was confident that the way Billie felt about things now was the way she would go on feeling for the rest of her life, he could try and help her keep up this charade. It wasn't as though it bothered him that she was presumed male by everyone who met her. But what would he do if, as she grew, she changed her mind and did want to do something more feminine with her life? Or what if, when she reached her fifth or sixth year at Hogwarts, she had a crush on a boy and couldn't do anything about it, because they'd already cast their lot? It might seem like an impossibility to an eleven-year-old girl, but Gideon could picture it all too vividly. He was already dreading having to face those conversations, because there wouldn't be anything to say, except that he was sorry — and to admit that he'd suspected this would happen and ought to have done something, as her guardian, to prevent it. He was an adult, after all, and she was a child — that meant that he ought to know better how to proceed.

He wasn't sure he did know better, though, which was the root of this nauseated feeling in his stomach. What if he pushed her towards the wrong choice and she regretted it later, or even worse, resented him for it? What they did between now and Hogwarts would alter the course of her life for better or for worse, and he was definitely in over his head in considering it.