Am I required to retrofit an egress window in a 1950s home to meet code?
The required egress window size is 5.7 square feet, except for first floor and basement window is 5.0 square feet. The net height shall be a minimum of 24” and net width shall be 20” wide.  (See ICC R310.2.1)

The window sill shall be not more than 44” above the finished floor and provided with an appropriate window well if located in the basement. (R310.2.2 and R310.2.3)

Yes, you are “grandfathered in”, (See R310..6), unless you’re remodeling your basement and adding a sleeping room. 

However, how do you sleep at night if you put a child or guest in that room? Do you at least have smoke detectors in the bedroom AND in the basement?