If you were born hundreds of years ago, would you have made it to the age you are now?
I'm 22, and probably not. When I was 8, I had appendicitis. I was given antibiotics, and it got better. Centuries ago, it either would have burst and given me sepsis, or they would have operated with no pain medication. I would have bled to death, or died from infection.
I also had pneumonia a few times. That probably would have taken me as well.