I can get energized interacting with other people, but it depends on what we're talking about. If we're talking about surface things, then I can get drained quicker. However, if we're talking about things that require more contemplation, like plans, ideas, specifically my interests, I can go on for much longer.
I'm more interested in concrete, tangible and objective facts. Like, for instance, I have a hard time just driving around my city aimlessly, but I want to learn more about it. So, I went and bought 2 big maps of the area. It gives me a detailed overview of the city from a geographical point of view, and suddenly I'm much less lost because I have a concrete external reference point that can serve as a mental image. That's really Te in action serving Si.
When I was 10, I was more playful and less serious or whatever around that time. I did a lot of stuff, but like I said, your type fluctuates a lot around that age. The only thing that really stays constant near that age is your orientation. As I got older, I'd say the TJ started to develop, and I grew an interest in that thinking oriented judging. It made me look at things systematically consistently, I grew competitive in a sense and started to define myself by accomplishments.
The thing was, in middle school, I used Te more to meet the minimum requirements of school. I found out what I had to do to just get by, and only did that, devoting more time to personal pursuits. I saw school as a requirement, but not an interest.
Well I would say I react strongly to the external world (my environment) but that doesn't make me extroverted, right? I mean, I'd much rather be alone than with people.
You need to stop this thinking. Extraversion != interaction with people. The two are correlated, but not equal. Increased engagement with the external world increases chances of interaction with people, but does not require it. They only enter the equation as a requirement if you're an FJ.
In the words of Yoda, "You must unlearn what you have learned"