Statistics will tell you that being over 70, or even over 50 increase your risks of becoming gravely ill with Covid19. There are natural changes in your body that make any illness harder to shake as you age, plus the older you are, the more likely it becomes that you will begin to suffer from health conditions such as heart disease or diabetes.
But being old does not mean you are unhealthy, it just means that you are more likely to be unhealthy. This is both the blessing and the curse of statistics, they show trends in a population, but statistics aren’t personal! Older patients without any chronic illnesses who are a heathy weight should remain cautious but not frightened. The vast majority will have quite mild symptoms and recover fully from Covid19.
I am more concerned about patients who are young and unhealthy than those who are old and well.