As women age, breast tissue is expected to get less dense. I don't think this is an absolute rule, though.
Breast density is more common in young and thin women. I would think that the density and calcifications warrant follow up testing. Have you had further imaging done? I ended up having a biopsy when I had density, calcifications and oddly shaped calcifications. I did not have cancer (but was scared). For whatever reason, more dense breasts especially when we are older is connected to breast cancer. https://www.mayoclinic.org/tests-procedures/mammogram/in-depth/dense-breast-tissue/art-20123968. And certainly it does make imaging harder to detect things. So, are you following up with anyone? Many women have results that cause a bit of concern and it is just fine. I'm not trying to scare you. But making sure you are prudent in evaluating this further is important.
I don't believe I have dense breasts (at least it was never mentioned). However, I did have a mammogram that showed calcifications and they had me come back and do another which again showed them. I then asked if I should stop taking my calcium supplement a number of days prior to my mammo and they said "yes". On my next mammo, the calcifications were gone.