My freshman year in college (back when we still rode horses to campus), I was a 17 year-old "dating" (that's what we called it back then, I think the kids call it something else today) a 24 year-old grad student. Now, she didn't know I was only 17 until a few weeks into our relationship and she wasn't my grad assistant. But still, there was certainly nothing predatory about it.
As you point out, there is a difference between teenage boys and teenage girls. If this woman was in her thirties, or older, I might see a more serious problem. What she did was wrong and she should lose her job, but prison isn't the answer here.
So if the sex's were reversed and you were girl, the guy would have been a sexual predator and should be imprisoned?
When I was 16 I was married, a father, and a deckhand (on the Mississippi River). (1950’s)
I think males on average were a litle more mature in those days. Females seem to be a little more mature today.