A positive about having your career chosen for you is that you don't have to worry about finding one. You get stuck with a career that you will have for the rest of you life and that won't change. It makes your life easier without all the stress of finding a career.
A negative about having your career chosen for you is that you don't have the option of what it is going to be. You get stuck with a career and you have no say in what it is. Also, you don't have the option to change. Once you get it, it's final.
If I were given a career at the age of 12, I would hate it. I feel like it would take my whole life away from me. I would have to live a life where it is just work. I don't have the choice to live my own life.