My T is a male 12 years older than me. I like the age difference because it's close enough to project the romantic/erotic feelings but big enough to support a paternal feeling (which predominates our relationship these days). He's just far enough ahead of me in life to have perspective on a lot of things I've faced. Not sure how I'd feel about seeing someone younger as I am so comfortable with someone older. But I think I'd be a lot more concerned about the "chemistry" than the age difference.
AG