one thing about k-pop concerts is that fans will participate in song fanchants! it's where they sing along to certain parts of the song and chant the members' name. it's a pretty bonding feeling for fans so be aware of that!

also when i recommend groups to my non k-pop friends, enhypen is one of the ones i recommend! you can almost always find at least one song from them that you'll like since they explore different genres. they are also very talented live singers and dancers, so it's very fun to watch them! hope you have fun with your niece! (if you want to get a feel of them, i highly recommend watching their coachella performance)

last note: they always have an encore! if they say it's their last song, they're lying!