When I was growing up, I was shy, no doubt about it. Except around my brother and good friends. And since then I've spent time and money getting over it, and I have. I feel comfortable meeting and talking to strangers. I give speeches, do cold calling, do media interviews. But I can still be shy. I can still feel introverted. Sometimes in writing articles about anxiety and recalling times I've been afraid, it brings the feelings back and I can feel withdrawn again, thinking of myself as anxious. Or I can pop right out of it and feel very much less anxious than most people.
The point of this is that part of feeling anxious is how we think of ourselves. Feeling shy and withdrawn is wanting to avoid trouble. Feeling unconcerned is often because of a lack of something rather than the addition of something like confident self-talk.
A natural tendency to produce excess stress hormones doesn't help. It tends to stimulate anxious thoughts and desires for withdrawing. But even then, having a goal seems to blow right through that. As long as I'm not adding anything. For example, adding the thought, "I want to do X but I'm not that kind of person."
Train yourself in good human relations and get yourself a good purpose and then give up adding "anxious personality" to the baggage you carry. Just let it go. Don't nurture that way of thinking about your personality. Forget about it. Literally, quit feeding it and eventually you may remember, "Oh yeah, I used to be shy."
Read more about dealing with anxiety here.