Personality is said to be either more or less fixed early in childhood or to develop gradually, Introversion and Extraversion being rather obvious in children.
Yet, as an introvert (with a real preference for introversion, who even score as an Introvert child in the mbti test for children), I was a bit shy (apparently that was a cute trait, I was known to be shy and nervous around people) and did not always get social conventions but was pretty talkative (driven by curiosity), often asking random questions about everything, telling stories, engaging in pretend games (I was a real story teller) and also... telling people things I was not supposed to say.
I also had friends (an occasional group of 4 girls, a best friend and some occasional friends or acquaintances I liked) pretty much up to the age of 9, until the social strucutre of the school became more complicated (I failed at "social skills" in primary school). I honestly do not think it opposes to the concept of introversion though some people argue it does. I think introversion had pretty much nothing to do with how social we can be or talkative but is more related to the way we process things and think but that's debatable.
I would never, as a child, go to parties (birthdays) or things like this but I was rather open to other children even though the relationships were mostly superficial (except for my selected one). I was also mostly passive (not really engaged in games which did not involve imagination and story telling) or leading (in story telling, and also in teaching) rather than friendly the way some children were but I guess it could be a case of being a T over being a F ?
The only introvert traits I can find in my child self were that I had a tendency not to talk to people I did not know (except other children), a strong tendency to be lost in my thoughts (I have always been known as the girl stuck in her bubble) and analyzing situations, social conventions, words (and misinterpreting some of them which was quite hilarious). And also, I prefered to interact with one person only - or younger children (and now, thinking about it, I'm wondering whether I am a repressed F or not).
I was pretty much bossy and loud sometimes, even had problem in nursery school because of that (I don't really remember, most of my memories are about my inner thoughts rather than my interactions with the world) and had to see a psychologist.
Intoverts are known to be generally quiet children. My brother was though he wasn't considered to be shy(and is less of an introvert now), but I still think that introversion does not oppose to being talkative sometimes. I don't know though.
It could be that I was developping my Ti as a child (though I'd argue that as a teenager, I was extremely emotional and naive and thinking inside the emotional box and strongly introvert) and needed to interact because of that since I did not have much access to books ? But to be honest, I've always enjoyed sharing my thoughts and knowledge with people, I am just more picky now than I used to be.
Any thoughts about that ?