This song was popular when I was 15, in tenth grade. The 17 year old senior girls might as well have been 25. While the Beatles and all their songs were very exciting and enjoyable, ( there is nothing comparable to the phenomenon today, ) this one did kind of leave me out in the cold.
Nevertheless, this song would not have maintained its wide appeal if it were not universally acknowledged that 17 year old girls are often highly attractive, No reasonable person thinks that this song is about pedophilia.