I have found most of my skills from either trial and error (lots of error) or in tutorials that are now available on the computer. Trying to teach or improve my math skills this late in life for me would be a lost cause. If I was lousy at it when my mind was young and fresh, I can't see me getting better now.
If you could offer different lectures to go along with what level people think they are at, that would be helpful. I do know some stuff and would be bored with a lecture teaching the basics. For people just starting into quilting, "the basics" would be invaluable! If you're going to learn, you might as well learn correctly from the start.