How did you decide you were able to teach?

There must have been a point at which you decided that you knew enough, were skilled enough, whatever enough, to be "worthy" of having your own students.

Or at least something must have given you enough confidence. What was it? Or if it was your own teacher saying something along the lines of: "You should teach", what do you think made them say that? Or if someone asked you to give them lessons, or you otherwise somehow ended up having a student or two, how did that happen or what made you feel you should continue?