What is it that you get nervous about before classes? When I think of failing my students, the reason is always being unable to convey the knowledge that I have; that I'd get flustered and wouldn't know how to say it so they'd understand. I know I'm good at using my knowledge. I feel like I can't be sure unless I give it shot whether I'm good at sharing it. And, if you don't mind, I'll reply to your second comment here, as well. I'd like to get into teaching in a uni or a similar higher-education facility because I find it easier to work with more mature people, mentally. I'm not sure if my degree would allow for it, so I aim at high-school level. Any advice on dealing with teenagers? The caveats, the ways to interest them?.. I know I'm getting that from the future courses, but I'd also like some experience from the field itself.