Thankfully no-one cares about those laws when having sex. And there's very rarely anyone watching by and asking your age.
I wonder how many percentage of people has actually broken those sex laws. It must be pretty huge number, like 80% or something like that.
Here the child/adult limit is 18 like in most of the world. But people between 16 and 18 can have sex with each other. But it's very typical that ages 14 or 15 has sex with anyone below 18, sometimes even up to 20 or so. And 16 to 18 years old has sex with over 18 years old all the time.
It's like drinking... Basically it's illegal under 18 but still people goes to bar at 16, and some starts drinking as early as 13 (the age when you move to junior high (grades 7 to 9)).