I think the fact that you had her at 14 and took on the huge life changing responsibility of being a Mum is laudable. I am a lot older than you, mid 40s. I have 2 teenage sons 17 and 14 and this is how it works in this house.
No one gets paid for chores.
No one pays me to cook and do housework, no one will pay them in future to do their own housework. Ds is 14 so in comparison he empties a dishwasher 3 times a week including a weekend load which has more stuff in it. So Tues/Thurs/Sun, I do Fri Ds1 does the other days. Ds2 strips his bed and loads it into the washing machine on a set day, Ds1 does the same and he puts the machine on.
Each child is responsible for a bin, so Ds2 is kitchen bin (Ds1 is recycling) so twice a week the bin gets emptied on set days as he leaves the house for school as they are going out the door anyway. One of these days is a bin collection day so they put the bin out and bring it back.
They both help with dinner and setting and clearing the table. No one leaves the kitchen after dinner until all things are in the dishwasher, some pans are hand washed, sides are wiped, table is wiped and dried too. Only then is everyone allowed to leave. It means one person isn't in the kitchen doing chores whilst everyone else swans around. They also have to keep their rooms clean, they are, and do some cleaning and hoovering.
From a young age any shopping trip went like this, I need to get you school shoes, if you are cordial and polite then when we get back home you are allowed tech/tv/xbox whatever. ie in very simple terms, I get what I want, you get what you want. This also translates to work, your boss gets what they want, you then get what you want - money.
Dh and I both had jobs from 13 however neither of my children have jobs. For us their effort needs to go into their school work. They get good grades and outstanding for attitude to learning. They know how much things cost from cars, to furniture, to holidays, to houses and what salaries pay. They have cash in their money boxes as they just don't spend.
What does she spend her money on now? Is she saving any of it?
Have you looked into student maintenance loans of what she would be entitled to if she was looking to go to university and more importantly have you and her Dad looked at what the Government expect you to pay towards her living costs? I don't know if your home is classed as the main residence but maybe some of this money you keep putting her way needs to go into a savings account for her future rather than her frittering it away on tat.
It is based on household income meaning if your house is her main residence, your partner's wages are taken into consideration for her loan. MoneySavingExpert