I always get confused when cis people use the word "transition"

I had a coworker at an old job who announced at a staff meeting that after lots of consideration, she had made the decision to transition. And I was really glad that I didn't immediately react, because everyone else at the table (all cis) somehow immediately knew this meant "switch jobs."

lol why?

Right? Like, I’m sorry, but that word is not for you.

I sometimes get confused with how other trans people use it. Like, when do they start counting??