I'm not sure. The most obvious change in me happened when I went to a new school at age 13. I was a lively kid, but couldn't make friends and got into arguments easily. I just wanted to play video games, but didn't know how to find anyone else who was interested. I felt like I was in a hositle environment. I became self-conscious of my quirks. I didn't get really bullied for them, just lightly picked on from time to time. I could't deal with my emotions and was impulsive, petty, and kinda antisocial. I didn't really have anyone I could talk to about that, not even in my family. I realised the best way to avoid humiliation was to become plain and quiet, which made me withdraw hard into online communities and defined who I am today.
On the first day of university, spending the night alone in my dormitory room, I had a breakdown, realising I was way in over my head. The lack of real life skills learned over the previous six years combined with inability to socialise ensured my three years in uni were just a protracted period of failure which ended with my dropping out.
In some ways I still feel mentally stuck around the age of 15 even though I'm a grown-ass man now. I'm learning to capture and recognise my emotions, as well as learning social skills that most people my age acquired many years ago. I'm coming back to that inner child I sealed away. I'm going beyond the embarrassment and reconnecting with who I really am, so that I can stop with my self-hate.
I got a job and moved out at 26. That forced me to talk to people and learn some social skills through trial and error. I could say that around 30 I became somewhat sociable.