Coleman is one of those fortunate people that look much younger than they are. She could easily pass for a 25 year old, which she easily accomplished in the series. That is likely to set an upper limit on theatrical aging.
Stock Photo - Anna Neagle as Queen Victoria in the musical "Glorious Days". March 1953 D1070A-003
Of course this picture was 16 years after the movie. I saw the actual movie on youtube but I couldn't find a picture of her as the aged queen. I remember her face was caked with makeup. It wasn't very convincing.