If both parties are truly in love with each other, then they can do whatever they want. Sure, the age of consent exists, but that's only to protect 'minors' from abusive adults, when most aren't.
Adulthood is just an act, a state of mind, a way of life, and maturity. Some people become mature earlier or later than other people, and some people never grow up like Michael Jackson.
I'm 20 and still feel 14, but no more school, I'm wiser, and my problems are worse. Other than that, my life is still the same. Hell, 11 year olds are way more relatable and easier to talk to than my own age group.
Turning 18, 20, or whatever doesn't automatically turn you into an adult. Everyone matures at their own pace, and that's where the government is wrong, since so many people break those laws WITH consent.
Age laws shouldn't have changed after the 1950's. Then people wouldn't make such a big fuss about teens and relationships with 'adults'. In the past, you were considered an adult after puberty.