It's the first on my calendar!
Thought this phrase was being a bit presumptuous, too. When I was researching weekdays for reasonable mnemonics to help remember them, I did notice Sunday being the first or last day was not global, but dependent on culture/religion.
I guess the Klingon who wrote that sentence had met different Terrans :)
Sunday is the first day of the week in the USA (and maybe other places). It's the last day of the week in Austria (and probably other European countries).
I think the audio has got a little encoding glitch here. Qov's "Qav" sounds like "Qagh" here, no matter how I listen to it.