I find that there is a different attitude toward aging in the US and the UK, and that you are considered "over the hill" at an earlier age in the UK.
I work in retirement propositions for an insurance company, and one thing that amazes me is that the retirment age is 60 for women and 65 for men. (I don't understand why the retirement age is lower for women, when they live longer.) And for public sector workers, the retirement age is currently 60, though that is going to go up to 65. You can actually start collecting retirement income when you're 55. In my opinion, a 55-year-old with experience would be at the peak of their career. I was surprised when I got my contract for my job and it said that my contract terminates on my 60th birthday; I'm 40, my grandmother lived to her 90s.
One thing I learned in research for my job is that older people in the US are more active than in the UK. People in their 70s and over in the US join gyms, go running, etc. (my dad who is 79 is taking tai chi); that's much less common in the UK.
Another thing that I have noticed, and this could just be my localised personal experience, is that you don't see stylish older women who look their age here. All of the women who dress fashionably seem to be no older than their 30s. It's possible that they are actually older, because you can't always tell someone's age by looking at them, but you rarely see a woman who looks 50 years old and is dressed fashionably. There seems to be an age at which you have to start dressing like a frump. This is very different than my experience in New York, where there were lots of well-dressed, fashionable women much older than 40.
At work, some women were having a conversation about dying grey hair, and there was an assumption that you automatically dye grey hair, as though no one could possibly want to be seen with grey hair. Lots of women in the US do dye their hair, but there are also women who are very proud of their grey hair. Grey hair can be very stylish and striking. I've even seen shampoo and hair colouring to enhance the beauty of grey hair in the US.
It's like once you hit 40, you are automatically unattractive, so you either try to pretend to look younger, or just give up on your appearance.
P.S. Just read Phillygirl's post. Phillygirl, as I said earlier 6O is the retirement age for women in the UK. (But that could change.) Sorry.