Spot on, especially the calendar!
The Day is mostly the same, but Day 1 doesn't mean it's the 1st of (insert month here), and the months are only written in a very fancy way, but you can easily translate it to our irl counterparts.
It's First, Second, Third, Early Quarter, Fifth, Half, Seventh, Late Quarter, Ninth, Tenth, Eleventh, Final.
I didn't include the month of when the story takes place, but you can assume it's somewhere during April (or if you want to use the in-world month system: Early quarter of Plenilune phase)
For example, Walter is born on the "4th of half Plenilune phase." It just means June 4th.
It has no bearing on the story itself, but it is important for world and lore building reasons.