How do you respond when a student insults you?

I teach middle school and had a 6th grade girl call me a “fat bitch” and I responded with “Well I am 40, whats your excuse?” The girl then started to cry and said she was telling her parents. I already alerted admin to the situation and they had a good laugh about it. I feel kind of bad.

Normally I have better impulse control over my mouth but this one just slipped out. Do you all ever verbally respond to being insulted?