Haven’t yet checked out everyone else’s answer. But I believe, that like sexuality, personalities with regard to trovertism is on a spectrum and the dial can move up or down depending upon one’s circumstances. I’m neither one or the other. Sometimes I’m more of one and sometimes I’m more of the other.
Take some from column A and some from column B and with six you get egg rolls. I don’t believe that anyone’s trovertism is set in stone. By simply, consciously changing your behavior or attitude (when you realize that it isn’t helping you or when other people point out that it’s causing them pain), even if you don’t want to, or it isn’t fun or comfortable, changes how you are. At least at that time that the behavior is changed.
I don’t go in for those personality tests. Many times the answers that you can choose from are simply not qualitatively accurate. I always look for an answer that is more like: Sometimes, but not if this or that happens. Or Never, except if it was an emergency. Or Always, but not if XYor Z was also happening. Or Most of the time, except when it’s Not.