I redshirted a year in college, ran one year, ran half of another year, then gave up.
That was decades ago.
Say I returned to a college with a cross country and/or track team now for some classes. Could I compete (ignore the fact that this would be ever creepier than 50-year-old guys running road races, but also realize that old guys playing DIII football always get on the news because it's fun).