I think there needs to be a much larger than one year gap between learning programming and teaching programming. It's just too easy to write bad code and not know it, or to think you understand something when you don't (see above OOP anecdote). All those bad habits and misconceptions will continue to rot as they are handed down from one freshman class to the next.

After you've spent years learning, practicing, and mastering a topic and you've tried and failed to find anything more to learn about it, then teach it to others.