AITAH for this casual joke

Was texting my gf of 3 months, saw her in the bg of a friend’s story of her eating a plate of food at a party and I screenshotted and texted her “u ate that sht up haha” as a joke, implying that she’s enjoying the food.

Next day she says she didn’t appreciate that comment and said it felt disrespectful to comment on her eating and didn’t understand what I got out of making that comment. Said it felt like an extension of asking a woman her weight.

I responded by saying it’s a joke just like how you’d banter and roast your s/o sometimes. I’ve never disrespected her looks nor how or what she ate. I always try to ask her to eat more cuz it seems like her meals are always tiny nibbles of food and skips meals sometimes. I said it makes me feel like I have to be on my tippy toes all the time when I say stuff, and her bpd doesn’t let her share what she’s insecure about to me easily.

And now she says I’m playing victim in a conversation where she’s trying to let me know how she felt judged and her feelings not being acknowledged.