Witnessed car accident?

yesterday i witnessed a car accident. a car was turning and the driver behind didnt stop going atleast 55 mph the speed limit the car flipped and landed in a ditch, skid marks are where i was 2 seconds ago if i wouldnt have been backing up to see the street name i was on i would have been dead. no one looked to be seriously injured but the lady that was flipped was pregnant everyone was just screaming. im still really shooken up and just can't seem to think what if i had not backed up. normal? By the way im only 16 and just got my license not 2 months ago.