Yep BIG dose of reality!
What kind of pay is she likely to get from a job without decent qualifications? Show her how much she'll ACTUALLY get by doing take home pay calculator on mse site
What is the job market even like where you are? (Some job sites show a counter of how many people have applied via the site for each job, when I was helping dd look where we are it was usually over 150 applications per job!)
How much are bills likely to be, what is rent, council tax, water, energy bills where you sw for property size she'd be in? Is it an expensive area to live? You could show her your bills too. She'll also have to pay for groceries, tv licence, Internet of course. Presumably she has a mobile phone - who pays for that? Is she used to having sky/Virgin/Netflix?
Train her/have her practice (if she doesn't do/can't already) cooking & cleaning: that includes:
meal planning and grocery shopping, how to shop on a budget, understanding use by and best before dates etc
Laundry - separating according to colour and fabric, stain removal, drying, ironing, folding & putting away
Hoovering & dusting - including skirting boards, door frames and hard to reach places
Doing the dishes (including burnt on food and cups she's left growing penicillin for weeks) & cleaning the kitchen including worktops properly, awkward to clean gadgets, sweeping and mopping the floor...
Cleaning the bathroom - including the toilet properly. Mopping floor etc keeping handwash topped up and clean hand towel always available, picking up discarded wet towels and putting in laundry.
Changing beds - including flipping mattresses
You could get a nice free deep clean out of this 