i must say that i had anxiety when I was a teen - I was a very shy child too. it wasnt until I was 16/17 did I start breaking out of it, but the anxiety still remained with me for years. I was scared to go anywhere on my own, had a fear of using phones to call/actually talk to someone and it screwed up my first job and relationships. Mainly its from my parents - my Mum especially from her upbringing. Her family were very business driven when she was growing up, we had a chain of shops back in the day and she was just landed with being in charge of it all from her teens pretty much. My anxiety comes from her and how failing grades or giving up anything is the biggest failure ever. I have a fear of failure and just stepping out against my Mum (tatoos is the big issue we're arguing over at this time actually).
I've 98% broken through any anxiety I had now, new home, travel, new friends, new job and new partner really did help me just "grow up" and get on with my life. I now have no issues in asking for pool cues behind the bar (that was one thing I was never able to do before and my ex used to always bring it up and say how pathetic I was about it). I also now work as a secretary answering phones and making calls. The making calls to strangers still bugs me a little if i dont know what im even really phoning for.
I did however get an anxiety attack in front of my current partner over a simple thing =/ I insisted on paying the parking meter, but my brain cant function maths very well and whilst I was trying to work out what change I needed, I started panicking and just broke down as a small queue formed at the machine. It was horrible. That happened early this year in fact, but has bene the only time recently ive felt anxiety try to bring be back down.
My personality has done well to hide anxiety by just being the over confident loud Rainbow Dash type person, because it works. Its like compensating personality traits vs flaws.