I am going to take a guess regarding how many hours you work. I think you work 15 hours per week.
You should feel proud of yourself.
You working in a restaurant is good at your age. You can learn how to do chores.
Cleaning, and cooking.
Well I don't know if you do any cleaning, or cooking, or maybe you do something else at the restaurant.
Here is the problem: Without having a high education, then a person doesn't have many options regarding finding a job. I think the best place, for you to work at would be at a restaurant.
I assume your mom didn't tell you that you could not work at a different restaurant.
I don't know if you considered volunteering somewhere. You can look into different industries to see which one you like best, and maybe you can volunteer somewhere in a different industry, and maybe you can learn something new.
You getting as much experience as possible should benefit you. I know it sucks working, for free, but maybe you can learn from other people, and maybe you might be able to get some new skills.
Lastly just because your mom buys you something, this does not mean you have to accept it.