Id try to banter a bit. Show her that youre a cool, fun guy. She seems friendly so it shouldnt be too hard.

"Idk, i usually just go as a sexy witch 😁"
"Look at u planning our halloween costumes already. So cute 😁"
"U just want a reason for me to walk around without a shirt 😁"

“For real, imagine how it’d be if both our styles were combined together...”