I don't know if I would've considered myself "precocious," but I was always a goody-two-shoes who tried hard not to get in trouble, and to obey rules and authority (so I didn't speak to teachers like an equal, but I believed in following rules), and my interests have always been rather arcane and different from what most people my age are/were into. (Other eleven-year-old girls were pretending to be horses...I was pretending I was someone out of Egyptian mythology.
Haha. That's funny, because I when was around 11 my family took me on holiday to France, and for a lot of that holiday I was pretending I was in the 16th century during the wars between Catholics and Huguenots. I'd just learned the word "heretic", and was saying it as often as possible (which really got on everyone's nerves.)
So I definitely understand having er... different interests to other people your age.
But I still related to other kids quite well at that age. It was during my early teens that I diverged a lot from everyone else.
For example, when I talked about my friend growing up and chasing girls, I did become interested in girls too. But I had these childish crushes on people, like "oh isn't she perfect", and I was mostly happy with the people staying in my imagination rather than being a real person. And the few times I did manage to talk to somebody I liked, it was absolutely disastrous. I haven't thought about this for ages, but I tried to make conversation with a girl I had a crush on by lecturing her on the behaviour of ants, which included telling her all the latin names that I'd learned. I was in my "ant phase" at the time.
And I also remember telling her how I thought it was really interesting that the word "mead" meant a type of alcoholic drink made by monks, and also was an old word for a meadow. I mean, what on earth possessed me to talk about that? God, it's so embarassing thinking about it!
But that is what I mean about being precocious as a child, and seeming more grown up, but the same qualities making me not fit in at all as everyone got older.