Hands up any non-Americans who think it would be weird for a 17-year old girl to be with a 18 or 19-year old boy?
Non-Americans because America is extremely hypocritical and prudish compared to Europe and we're all well aware of it so no need to. Although even in the US the most common age of consent is 16 (only in 11 states have it at 18). In Europe only Malta has 18 and Malta is half the size of Rhode Island by population and ten times smaller per area.
American here: When I was a senior in high school, I dated a junior. She was 16, I was 17. I graduated, she turned 17, I turned 18. The next semester I would occasionally leave college and pick up my girlfriend from high school.
Seventeen is also easier to fit into lyrics. Dancing Queen by ABBA. Sexy + 17 by the Stray Cats (although the song was about ditching high school classes). At Seventeen by Janis Ian (who was singing about herself at 17). Paradise by the Dashboard Light by Meatloaf (again about both being high schoolers, but he’s a bit of a creep anyway).
ETA: It's just kind of a natural part of the life cycle of a musician that--barring Disney child starlets and other abuse cases like that--you're in your 20's or 30's by the time you're playing to a concert hall full of teenagers, so there you are, 30 years old, singing songs about teenage relationships.
Oh, I mean the guy himself. I know two women who knew/worked with him.
I always took Paradise as more funny than creepy because I interpreted it as a parody of stereotyped guy/girl behaviors and agendas rather than advocacy, but the guy himself wasn’t someone you’d particularly want to see your sister dating.