However, the only person really in a place to tell you whether or not you are ready for sex, is yourself. So I prefer to see that particular law as more of a guideline; if I feel I'm ready to perform a fundamental and entirely natural human function, then that's what I will do, and no law-maker that has never met me will tell me otherwise.
Just because the law says something is illegal, it doesn't automatically make it 'wrong' in a moral sense, just as actions that are legal are not always 'right'.