It is at this stage of a woman's life that lifestyle choices begin to play a big role. Things like healthy eating, regular exercise, no smoking, limited drinking and regular sleeping start having an effect on someone's health. In your twenties, your body can still recover relatively quickly from something like a hangover – it may take a lot longer in your fifties.
Many of the problems women experience during this time have more to do with our society's focus on youth, than with actual physical problems. Most women can indeed continue to experience sexual pleasure well into old age. Generally, the rule seems to hold true, that for women who have always enjoyed sex, menopause will change very little.
But for those who have never enjoyed sex, the menopause will bring about a decrease in sexual interest and enjoyment.