You can say "Baby boomer", and "Gen Z" isn't banned in itself but it's obnoxious when older people complain about people younger than them -even if seemingly rightfully-, so such discussions may often get deleted

You can think 2006 in specific is the cutoff year on Heyuri for possibility of banning new words/trends (eg. boxxy of 2008) but it's often applied case by case. Though for words, it's not my native language so I leave applying specifics to mods when in doubt
And posts submitted in good faith won't get you b&, so don't be too hesitant of posting what you have in mind to the point of not making posts u intended making, as long as you won't get upset if your post happens to be deleted