I'm 37-years old and my son is ten. I like to think I'm a pretty savvy dad, with an advanced knowledge of video games and new technologies, and my ear to the ground with regards to today's pop music and pop culture. When my son's interests diverge from mine, I usually know enough to fake it.
The great exception to the above is Pokémon. My son loves all things Pokémon, and has for years. Recently, he's been doing a deep dive into old titles for the Game Boy Colour and Game Boy Advance. Some of these games date back to the late 90s, but I'm so completely clueless when it comes to Pokémon that I can't even fake it.
I just missed Pokémon. It took off when I was far too old to care, like Tomogatchi and Pogs. Even after reading the Wikipedia page I don't get Pokémon enough to fake it.
At least I was savvy enough to score him 21 Pokémon roms and emulators for Game Boy Colour, Game Boy Advance and Nintendo DS.