If she was only younger for Arkadina, it would have been beautiful, I say younger as Arkadina withdraws from society due to the loss of a CHILD, A SMALL CHILD.
Actually, that's a good point, Random, although it's Ranevskaya you are talking about, not Arkadina.
For what it's worth though the part is still often played by much older actresses; not too long ago by Charlotte Rampling, and only a few seasons back at BAM by Sinead Cusack, who, while only six years younger than Barbara, looked amazing and much younger than her years in the role.