This all feels natural to me in structured thought and interests, and I am only scratching the surface. Looking around at others I grew up with, I thought we were all being a bit cagey or private about our interests for whatever reason, but I am starting to think I assumed wrong, and maybe I'm the odd one here.

Are you asking if you're the odd one for having interests this varied or deep, or are you asking if you're the odd one for being cagey or private about your interests?

If the former, no you're not odd at all. If the latter, I wouldn't use the word odd specifically but most people probably aren't cagey/private regarding their interests by default. I was also raised around people who had a distinct lack of curiosity, due to what sounds like similar reasons. It is a bit hard to learn as an adult how to share enthusiasm for something with other adults, especially when coming from that kind of upbringing though. I guess it just self-selects for friendships with people that really share your passions though?