How old is old

I think 70 is old.
When people reach the age of 70 they start to experience Alzheimer's so they (memory loss).So they may forget family members,names etc. They may even lose there know how to things

They will half to go to retirement homes because they can't take of themselves anymore.So The nurses. and such will have to help them with anything such as bathing,dressing,and sometimes walking

By the time your 70 they also lode there ability to hear things around them. That could be dangerous such as a car going by while crossing the street.
That is why I think 70 is old.