Work until you no longer have to introduce yourself.
"You are going to be spending a lot of time working, so you better love what you do. And I’ve switched my career a couple of times, and I think that that was what gave me my North Star—you have to love what you do. Because you’re trying to inspire a lot of other people, you’re spending a lot of time doing it, and it’s got to be rewarding."
A worthwhile read, I think.