by your ask it seems that you had a few share of bad experiences with people with so called niche interests, and though there are assholes everywhere I do recommend having a few friends with very specific interests.
Something I like to keep in mind is that my interests are not fixed, in fact in most cases it's something that it's shared and developed among a community of people. i've introduced my friends to some of their favorite music, and there are tv series I've only watched because my mom suggested to.
I'm not a film buff by far, and I have met a lot of annoying ones, but some of my most beloved friends are really into films, and dedicate a good time of their lives to their hooby. I love listening to them talk, and learn about the effort they go through to watch a specific movie, sometimes they have to test lots of torrents or find a physical copy in most random place in the world. Lucky for me, because of them I don't have to commint the same energy, they share their drives with me, invite me to festivals I had no ideia existed etc. I don't like nor watch everything, but it's so nice when we leave a movie theatre and exchange our different perspectives.
All of this to say that you don't have to prove yourself when it comes to your interests because all knowledge is shared, the world is yours to discover at your own pace with the people you enjoy the most.
