The issue of consent and kind of the subject of this post was treated rather extensively in this thread:
Linky
Ages of consent are legal fictions and by definition are not supposed to reflect reality but give give a parameter that rule everyone based on what the legislator at the moment of writing the law considered to be "normal". That's how in the US they very oddly came to decide that at 18 years you're able to kill people in a war and have sex on camera for the entire world to watch it but you can't have a beer until you are 21, cause you're not mature enough at 18 to control your alcoholic impulses, stupid if you ask me, but that's the way it is and I think that's what it should all come to in the end. As long as the law is one, you must obey it or attain to the consequences. You don't agree on what the law says? Try to change it, there are many ways to do so, but if you break it, whether it seems stupid or not to you, you will have to pay.