Idk about you guys, but as someone with two older brothers, it is definitely NOT a pleasant thing to see your older sibling naked, you might forget about it, or it might be a scarring image that you can never remove from your head. Yeah, she's 10, but she will definitely remember it. I'd probably keep quiet about it as to not rub it in and lessening her chances of forgetting it. Also, for those who don't think it's weird, ya nasty.