Girls: Can you help me?

I've been going out with my girlfriend for a few months and she's the sweetest girl ever. During the summer she sometimes wears crop tops and matching skirts because they're cute and fashionable. My grandparents and aunt & uncle were over at our house and she stopped by & it was a day she had one of her crop top outfits on and I could tell from the first moment she was really embarrassed about it. A few times she tried to pull her top down to cover some skin & she told mad afterwards she felt like a slut in front of my grandparents. I know this might be weird, but I found it so HOT that she was showing off some skin around my family. Is this weird of me? I hope she isn't a slut for doing this?