Interesting read that is interesting to read. Add more specific events, don't talk about things such as the main activity instead explain how it happened. A few things i would change :
All thirty eyes were clearly on me.
were staring at me.
e, by being an active participant than being just an observer. I
just being an observer
ss by improving my Japanese first and coming up with new ideas for classroom activities.
by first improving my Japanese and then coming up with ideas for classroom activities.
Over all I think it shows your initiative and good luck to you!