How old do you have to be go homecomming?

There's no single age requirement for homecoming. It depends entirely on the school's policies and whether it's a high school, middle school, or even college homecoming. High school homecomings are typically only for students currently enrolled in that school, meaning you'd have to be of high school age (generally 14-18). Middle school homecomings have similar age restrictions for their student body. College homecomings often don't have age restrictions but usually focus on alumni and current students.