AITA for calling her “busty” on a date?

I 29m recently went on a second date with a girl (21F), Vicky, in my small town. We know a lot of the same people, friends and acquaintances alike, but basically just met. Things were going great at first. Our first date was coffee and this date was a nice dinner. 

We got food and a mutual came up. This guy who dates a lot of girls. We were roasting him as never going deep with any one. She brought up one who she wished had hung around. Said she was charming, fun, and sporty. Vicky herself is super fit.

I was trying to figure out who she was talking about and I said, “I think I know who you mean. She was the busty one?” She seemed disappointed and blinked a lot and said yes. I could tell I offended her and I was like sorry I didn’t mean anything by that, just something I remembered. She said, “You don’t comment on another woman’s body on a date.” 

I said OK i understand and tried to move us on. But the energy was bad. I texted after and she said she didn’t see this moving forward. 

I guess I am just confused as I don’t think this is particularly or offensive or anything but maybe there’s something I’m not getting. AITA