Running is a practice, not a performance. You don't need to be fast. You don't need to be thin. You don't need to be "disciplined" in the way the movies show it. You just need to be a person who puts on their shoes.
You can be a runner with a soft belly, with grey hair, with a stroller, with a busy schedule, with walk breaks, with used shoes; there is no entrance exam, no pace requirement, and no committee deciding if you are legit enough—the simple, radical act of putting on your shoes and moving your body is enough.