"In fact, scientists think that female desire might go up just as fertility starts to decline toward the end of your 20s. For women in their 30s and early 40s this time of life may be when your sex drive is strongest. One study showed that women between 27 and 45 had more frequent and more intense sexual fantasies than younger or older women. They also had more sex and were more likely to have it sooner in a relationship."
What you are reporting is right in line with that. Hormones play a part but also where you are in life. Older women have often transcended at least some of their societal programming and may now be more self-confident and willing to pursue their own desires.