The law literally treats assault differently depending on how much damage the perpetrator did to the victim.

Also is the emotional impact the same of a 17 year old girl having sex with a 24 year old man as a 17 year old boy having sex with a 24 year old woman?

It's certainly an interesting question and I'm not sure if there's been research done.

Society is going to call a girl a whore for her sexuality while men are commended for getting laid in general

Beyond that, the majority of straight relationships have the man as the older person. And thus in some ways the 24 year old man is going to have more power over a 17 year old woman than a 24 yo woman over a 17 year old man.