fluttershy lives at her animal sanctuary in ponyville, working alongside vets and rescue charities to to house and nurse sick, injured, or traumatised animals.  
she lives here with her “husband” discord, lord of chaos. theyre not married (discord views marriage as a very pony thing, while fluttershy isnt one for large events) but they still see each other as husband and wife.  
together they have just one daughter, iris. fluttershy and discord love her with all their heart. they only have one daughter - the reason for this, is during fluttershy’s pregnancy with iris, she grew very sick and very narrowly escaped death. the two are fearful of that happening again, and so instead pour all of their adoration and care into their one daughter.  
fluttershy suffers anxiety, particularly generalised anxiety disorder. she’s much better at managing it than she was in her youth, currently on medication, as well as attending therapy and managing her symptoms - but well, that’s never going to change the fact she’s quiet and introverted - but thats okay, thats just who she is  
discord has helped her a lot in that process. admittedly, he’s the complete opposite of fluttershy - boisterous, loud, loves pranks, etc, but having someone confident around helps her feel more confident in herself.  
between raising a draconequus cub and running her animal sanctuary, fluttershy found herself with a lot less free time and a lot more stress - so, in order to be able to take care of herself a bit more, she has quite a few helpers on the sanctuary. the most notable over time are bird song (twilight and dash’s daughter, who comes to care particularly for the birds housed there when she’s old enough) - and tree hugger. it should be noted that fluttershy, after years of therapy and managing her anxiety, is much better at handling her emotional wellbeing and self care than. well uh. any of the rest of the mane six lol  
this allows her more down time, as well as more time for her friends and hobbies - she continues as a member of the pony tones, now working up to perform in small to moderate sized crowds, as well as attending a group therapy/anxiety management group in ponyville… but sometimes, its just nice to curl up in the cottage on a rainy afternoon, with some tea, and just relax. we stan a queen who takes care of herself.  
ive always thought of fluttershy as asexual/biromantic. she isn’t sex repulsed, but mostly just “did it” when trying for a child, and is otherwise unbothered by it. discord is okay with this obviously.  
fluttershy is about average height (although, compared to apple jack or to discord, she’s p tiny), and fairly think and lanky. also like the other older headcanons, her mane is beginning to grey, and she has grey/lighter markings around her face.  
like the ones before, she’s about the age she was in the season 9 finale. i have. no idea what was going on with her hair in her official design im not gonna lie.