Is being a Fire Sergeant in one's 30s considered high-ranking?

A woman I was recently introduced to and have been getting to know is a Fire Sergeant in her mid-30s..
Is this a high rank?
I don't know much about fire service ranks.
I was told I can just think of her as a practitioner/field officer.
She doesn't talk much about work, so I can't really tell.
The information I've gathered is that she works shifts as a practitioner, and her job satisfaction is just so-so; that's about all I've heard.
Our personalities match well, but
since she works late into the night, she often seems tired during our dates;