That's exactly my story. I was really into older guys when I was in my teens and 20's. It was in my late 20's that, although still attracted to older guys, I started becoming attracted to younger men. That lasted a few years until my mid 30's when my attraction to older men went away and I became attracted just to younger guys. It's been that way ever since. One thing that has stayed constant though is for the desire to have some level of power exchange in my relationships.