Well I wouldn't say that it's wrong, so long as both persons truly loved each other and weren't in the relationship just for physical means. If the girl truly loves the guy and vice versa, and the parents are okay with it, then go for it. In my eyes its no different from a 20 year old woman falling for a 28 year old man.
Yes not only is it wrong its against the law the 24 is taking advantage of the 17 year old
I don't think its right but in the law there'd be nothing wrong with it.