Kosher as in the packet is there and it doesn't seem to be missing anything (ie particular forms a squadron may ask for).
As for when they notify those for interviews, every squadron is different. Usually it's about a month prior to the board. Sometimes they advertise when they'll notify by...and sometimes even if they say a certain date, they may be a week or two late telling people.
Also, most squadrons are good about either sending a letter or email to notify those who did not get the interview, and some squadrons even go as far as to outline what separated you from the one's they chose, so you can improve things for the next try.
Best of luck