I had a g/f when I was 28, she was 39, if that counts. It was a great time.
Maybe a special situation, as she was just getting divorced from her husband, who was her first boyfriend and whom she married right away.
We experimented a lot, as he seemd to be really a boring person by ANY means.
It did not last so long but we seperated as friends, and still, when we see us by chance, we both smile with fond memories.