Cant figure out my brothers step daughter

I have wanted to bang my brothers step daughter for a couple of years now , she's 22 at the moment so its always been legal. Anyway I'm terrible at reading women's subtle hints. Probably because I'm very direct and clear myself, it's difficult to notice and interpet things. I kill at jeopardy so I'm not stupid but seem to lack understanding.

. She was actually raised in the middle east til she was 12 I think. She always came off as a good little muslim girl, for the most part, but there have been some moments where I wondered if she was flirting with me. A back rub once, going out to smoke with me, little stuff like that

. Been finding out though that she isn't really a perfect little muslim girl, smokin weed,,dating the bad boy losers. Drinking. And finally last month , knocked up outta wedlock, yeah, she had me fooled, now I am wondering if she is a dirty little ** ** too

My brother, her and I were sitting in the living room, taking turns blathering on about ancient warfare and I decided to put on a YouTube video about ancient Rome, my brothers step daughter (step niece ?) had her head buried in her phone, she could not have cared less about what era Romans wore chain mail armor in.

It went like that for a while until the video started talking about ** in ancient Rome , women having s3xx with bulls, that sort of thing.

. I saw her head whip up and start watching it intently. My brother had left the room for a bit on some errand by the time that part about the roman women getting freaky with the wild life was over, so I decided to crack a joke.

. I said to her in a joking tone "turned you on didn't it" ---"didn't it?"

. I was expecting an affirmative And drawn out NNOOOO like young people use or some variation of "get the fv*k outta' here

. But she turned her face away from me and looked down, because of her hair, I could not see her expression.

. I added " did you?" Because , ** I still don't know, what her reaction meant.

. Was that embarrassment at the topic ?
embarrassment because she was turned on ?
grossed out ?

years ago I saw another girl do the same thing when a buddy said to a girl " oh you're bored, do you want us to ** you?" Also in a kidding jokey tone.

. She turned her head looked down and did not reply too

. WHAT DOES THAT MEAN ???