When I was growing up, I wasn't an extrovert. If anything, I was an introverted kid and a very average pupil at school. I was very quiet.
There is no such thing as a pure introvert or extrovert. Such a person would be in the lunatic asylum.
One of the things that is assumed about actors is that they are extrovert, which is almost never the case, in my experience.
For an interesting nonfiction read, I really enjoyed 'Quiet' by Susan Cain. I read it with my husband, who is a true introvert, whereas I am an introvert masquerading as an extrovert.