Cancer is triggered when there is a change in the DNA of cells that cause them to start dividing abnormally. These abnormalities become more common as we age, and our cells, and the DNA in them also ages. It's like if we copy a piece of paper, then we do a copy of the copy, each one is not as fresh or good quality as the first one. Statistically, most cancers are more common the older we are. Cells in younger people naturally divide faster so cancer can progress faster or sometimes be more aggressive, but not always. I am 42 and got hormone +Ve bc with no significant family history so go figure.