Similar here @arpie, although I was 47.
2.5cm ductal tumour felt 10 months after mammogram and 8 months after ultrasound. I never knew I had dense breasts until it was noted on the MRI report after my invasive cancer diagnosis - ">75% fibroglandular and complex imaging appearances".
BreastScreen WA have invited me to provide feedback on their service, so that will be one point I hope to make. I feel it is an improvement they can make relatively easily, but could have a major positive impact.
I would have been happy to pay for more intensive screening, but you can't make that choice without the background knowledge. Given my pathology is triple positive and the HER2+ makes it fast growing, it may not have made any difference - I understand that a scan is just a single shot in time. However, it does leave me wondering if I could have avoided invasive cancer or been diagnosed at lower stage.