This is a very nice photo. I like how the shadow of the street light (?) points directly at the lady, and how you give her all this space to look into.
And does your question mean to say that she seems unhappy to you? Only because she's old and needs to rest on the bench after her shopping at Sainsbury's?
I asked my mom the question whether growing old meant growing increasingly unhappy when she was around 60 or so and I thought that 'very old' (I was then 25), and she said "No. Why. Each and every age has its advantages. Little disadvantages to each and every age, too, of course. But you can enjoy life at all stages. Things change, sure. We change, too. But you need not stop enjoying life."
I think her philosophy got challenged in the last couple of weeks of her life when her cancer was positively killing her, but before? Not for one moment!