Teaching English

I've got a new job teaching English to Japanese Jr High students.

When I signed up for this job I was excited - it pays well, it will fill my time, it will help me make Japanese friends... Now my point of view has somewhat changed.

I'm nervous about teaching because from what I can tell the Japanese English teachers aren't prepared for me.
They've changed my schedule a few times, and instead of saying "come in at 9:00 for a class at 9:30" they say "see you in the morning".
Instead of saying "This is what the lesson is about, here is your part in that lesson", They say "you will assist us by speaking English."

A few days ago, I said to myself -- this is OK. This is how I run my life anyway, I don't like to prepare details and am pretty good at flying at the seat of my pants. The closer I get to the day I start class the more nervous I am getting.

The one solid thing they did tell me to do was to prepare a 15 minute speech for the students. In the speech, I'm to introduce myself and tell them about me. Easy enough -- but they also said to make it interesting. Jr High student have a short attention span and it would be wise to bring pictures or music to keep them engaged.
YIKES! What English words do they know? And how do I know what is interesting to Japanese Jr High students... I don't even know what is interesting to American Jr High students. =)

Needless to say -- I'm afraid this "teaching english" thing isn't as easy as I once thought.