I'm not trying to offend your friends so don't take this the wrong way but I think they are way too immature and insecure. Usually, teens are the ones that worry about liking stuff that they are "too old" to like because they want to look cool and mature. Am actual productive, mature and happy human being couldn't care less about that kind of stuff. Also, everything we like is kinda "nerdy" to me. For example, I bet they don't question people that like sports or rock music and it's the same in the end and there's nothing more functional about it. I don't see why, but society considers a dude that knows the name of every player in a sports team as someone cool at least acceptable and the same applies to the dude that knows a lot about rock bands or a lot of actors and actresses. They also don't see the irony of saying that stuff and yet they were making line to see Toy Story 4 or Avengers: Endgame. This is coming from someone that loves all this mentioned stuff.
Be yourself, enjoy life and don't feel shame for the stuff you like. I'm 30 by the way, and as you can see many of us have already families or a significant other so there isn't an age for any of this. To be honest, after reading that they even make me cringe a bit because they sound like they never outgrew their highschool versions. That being said, I do hope you balance your life because there are so many things to enjoy and focusing on just one isn't healthy either. I'm curious about what they would reply if they saw my message haha. I hope they would understand what I'm saying instead of feeling attacked though.