"I'm tired of having to be grown up."
Bloody hell, I don't know any adult who doesn't have some sort of anxiety daily. "Damn, I slept through my alarm - boss is going to kill me if I'm late today before the big meeting!" "Oh no, Sean only got a D in math this semester; I have to call the teacher." "Shit, did I forget to turn off the oven before leaving?"
Yeah, that's minor stuff but major or minor, most people have some level of stress every day, including even the most organized people.
She's lucky - she has a warm, dry, safe place to live, an income, food in the cupboard & people around her. No loved one is dying, in jail or anything of that sort.
She seriously needs to practice her anxious face - that expression looks more like she's zoned out starting at one of her crayoned mandalas.