[There be spoilers here]
I was checking into the timeframe for Mahoro's "birthday". The preview at the end of episode 7 states that she was created 9 years and five months, prior to that point in time. The problem is fixing exactly what date she made that statement.
The fall term seems to begin right around the first of September, and that would be when Ryuga first appeared, but Mahoro states that two weeks had passed since his appearance. The time flow in that episode is difficult to follow.
A second question to ask is if the countdown is the days at the beginningg of the episode or the end. I have done my timeline calculations based on it being the end of the episode.
In episode two, Mahoro states that she is 9 years and two months (before she is cut off by Suguru). It does seem like she can give that information down to the second if necessary. We do know the exact date though of this episode. It occurs on Tanabata (July 7th). That would mean that the latest Mahoro's birthday can be is May 7th. I'm placing my bet on sometime within the first week of may for my story.
As for the year, we have a hint in episode 3 when Mahoro looks at Suguru's calendar. July 20th falls on a Thursday. The years that fit that requirement are 2000, 1995 and 1989. Since the conflict suposedly began in the early 80's. I think 1995 fits the bill the best for a "current" year, making Mahoro's birthyear 1986 (assuming she was commissioned soon after the confilct began).
This is just my take on it. For my stories, I don't use an absolute year. I just use a year 1, year 2, year 3 designation on my calendar.
