I consistently rate as an I, yet most people I meet would consider me an extrovert/E. Part of this is because when I'm meeting with people, I can be E, but it's not necessarily my default behavior (or what I'm most comfortable with, to be honest).
If it's not what you're most comfortable with, that means you're not actually an extravert. An extravert is someone who is energized by dealing with the external world, and an introvert is energized by dealing with their internal world. There are introverts who are very outgoing and good with people. It just tends to take a lot out of them.
I know - I was replying in the context of the parent's comment:
"I'd wager a guess that when you're a startup founder, it greatly helps to be an E."
Not sure if it necessarily helps - it's going to depend on what your other skills are and who, if anyone, else is on your team. I'm an I but get mistaken for an E.
