My thought is that it sounds like you really don't want to teach, and teaching is for people who enjoy teaching.
For an easy example, do you answer lots of build questions here on the forum?
Do you help newbs out on a regular basis?
If not, I think you're just fooling yourself, you really don't want to get involved with this teaching gig, you feel forced to do it.
Maybe you feel like you BS'ed these people about your abilities...and that's not a good enough reason to accept students.
I would not want to be your student knowing what I know about the reasons behind your needing to teach, your heart's not in it and possibly your talents aren't really there either (yet? I don't really know)
Why not just go back to the co-op and tell them how you really feel about it, just tell them the truth, and see if they have some other option for you, would you be relieved if they said no problem bro, we'll work out something else more amenable to you?
Or maybe if you ASKED FOR HELP one or two of them will step forward and help you get set up to teach and actually help you through your first few classes, it sounds like the kind of place that might be willing to help you out if you asked.
BS'ing yourself and/or other people usually has no real payoff.
Ponying up and asking for help, or just being straightforward with people, sometimes has payoffs that you would never have guessed could happen.
all great points. I think the major problem is not lack of desire, but just being cautious about whether I've got the skills to pay the bills. And as I'm English, I err on the side of self-doubt, rather than on the side of self-belief.
the idea of teaching the class I find very exciting, and I'd like to be able to pass on what I know.