I am primarily an introvert, and I consider myself a writer. It is easier for me to be in calm one-on-one situations.
However, I am great at faking it as an extrovert. People often will say, "Well, that's easy for you, because you're an extrovert..." which I certainly am not! Being loud, outspoken, and assertive is draining for me.
I too have worked in sales as an introvert! It is absolutely possible. It just means that being around people all day won't recharge you, and you feel quite spent at the end of the day.