As a child, I was never very energetic, but I was very social and friendly to strangers. I loved to talk to people. I was, in fact, so friendly to strangers that my mom was terrified someone would snatch me.
Unfortunately, I was the smart chubby girl who was always teacher's pet, so my peers beat me into submission. I regularly cried myself to sleep even as young as 6 years old. I remember fantasizing about being hit on the head by a falling brick so I could be stupid and happy like everyone else seemed to be.
Eventually, the years of brutal teasing and exclusion from classmates, a physically/emotionally abusive mother, and worsening Bipolar disorder leading to several hospitalizations led me to stop leaving the house at 15. I was diagnosed with Avoidant PD and I eventually dropped out of school.
So no, I wasn't always like this. And even when I'm outside and I'm terrified I still behave in a friendly, chatty way with strangers. I still love talking to people and am always desperately hurting for company. I'm always so lonely it just kills me. But in the battle between anxiety and loneliness, anxiety usually wins. Hopefully I can fix it someday.