Tenchi's Birthday

[takahata]

I am puzzle over the date of Tenchi's birthday.  According to the fan based timeline feature in AstroNerdboy's blog, Tenchi was born in the year 1976.  In the Tenchi Muyo Wikia, Tenchi's age was 15 when he had accidentally released Ryoko from her prison cave cell.  Tenchi was a high school freshman before his high school was destroy.  Before his high school was destroyed, Tenchi had return to school.

Since Tenchi was fifteen when he had accidentally released Ryoko, his birthday will have to be in either September or October. After his high school was destroyed,  Tenchi had to quit school. We know one of the few reasons why Tenchi had to quit school. Sometime after he had quit school,  Tenchi was able to resumed his studies. He did have two tutors.

Does anyone know the exact date of Tenchi's birthday.  The date of his birthday must be after the day when Tenchi's high school was destroy.

[shades of blue]

1976年
   信幸の長男、天地誕生。
   
1980年頃
   天地の母、死去。（原因・経緯は不明）
   
1992年 ８月
   天地(16歳)、夏休みに柾木神社で修行中、祠に入って魎呼の封印を解いてしまう。（すべては勝仁が仕組んだものであった）
   
1992年 ９月
   天地、倉敷西工業高校(天地の母校)の屋上で、復活した魎呼と出会う。
追いかけっこ(魎呼の破壊活動付き)の結果、高校がガス爆発事故に陥る。

阿重霞・砂沙美の乗る『龍皇』、地球に到達、時間凍結を解除する。魎呼 (と天地)の乗る『魎皇鬼』を捕獲するも返り討ちに遭い、
結局両者とも瀬戸大橋に激突、大破する。
この騒動の最中に天地、阿重霞・砂沙美と出会う。

翌日以降、魎呼・阿重霞・砂沙美は、倉敷市内から柾木神社の隣に転移させられた柾木家の「居候」となる。

http://postimg.org/image/qy8xipjad/

Seems to imply the school blew roughly a month after turning 16.