I still remember the first day at pre-school. I really didn't want to go (shy + stubborn) but my mother guided me around the school and tried to appease me by saying I could skip that very first day. When I saw my future teacher, I knew I'd have a wonderful time and I begged my mother to leave me there, immediately. The rest of the year I loved going to school and was said to be very outgoing.
The next year was a disaster. Bitch of a teacher (in my perception), I revolted, not at school (where I pretended to be a good pupil; it's like going into a shelter during war) but at home, opposing my parents every morning when they wanted to send me to preschool. After a few months I had become so unmanageable that my parents sent me to another school.
Another great year followed, where I could be myself most of the time. I came out of my shell, lead a group of friends, etc. There were some tensions (me not agreeing with school staff, and rather than continuing a battle I saw I couldn't win, I secretly tried to outwit them, which wasn't appreciated the few times it was discovered). But all in all a happy year.
Then my parents moved to a large city with smelly air and a huge, overpopulated, intimidating school, where I withdrew again. I can't complain (I had a reasonably good time), but I believe my defensive stance made me a more introverted & shy person. From late high-school till now, I've been trying to reverse that. It's a very slow process. When it comes to expressing a big emotion, there's a real power struggle going on inside of me! (Do I or do I not show anything, and how much?)