OP
you're bizarre!
If someone talks about an arcane thing that I am interested in - that makes me happy- because I finnally have someone to talk to about my special interest.
When I was your age, or slightly older, guys my age (whom I knew) would only yak about: fixing cars, sports, or illegle drugs. Or about getting laid (which I found interesting-but still know nothing about even now- so I dont have much to say about it).
So I can not relate to you being "jealous" when you find someone eager to talk about what you find interesting. Just be happy about it- and engage with that person who shares your interest.