That makes sense.
Was it okay that I asked the question? In the end I just wanted to be enlightened and I got many helpful answers (including from vadge, EgoRod, Roy, mikenmark, cake and many more).
What I can summarize from all the great answers is:
the boy in the szeaniro could have been 18-19 years old (legitimate age)
it's all fiction anyway
if story is based on real experiences, then was from a time when Madonna herself was 18-20 years old (also legitimate age)
even if the teenager was 15-16 years old, that can be overlooked because Madonna was also young and everything sexual in the story was consensual
and as I said, it's all fiction and the book is about presenting the reader with different sexual fantasies and perspectives
Actually logical when I think about it, but sometimes I can't see the forest for the trees. The same thing happened to me in therapy lol. I realized so many things there that are actually obvious.