I know that Wattpad is a place filled with people writing out their imagination. Some typical Wattpad careers are doctors, nurses,teacher, secretary, and etc.
Just from the few career I have mentioned some of them require going to college and extra schooling. While others don't.
But the authors are making like 21 year old doctors and nurses . And I'm laughing cause I want to be a nurse in the future and I already know it's a slim chance that I will be a nurse at 21.
But it's for the sake of the plot. They want the main character to be "young" or whatever.