Before a person can know when they are "ready" for sex, it is important for a person to understand what sex is and is not.

First, sex cannot be reduced to a mere physical act. Every aspect of the person is affected: the body, the mind, and the intellect. Some people think that because they have strong feelings for their partner, they are “ready” for sex. That is not the case.

Second, just because your body is biologically capable of sexual activity because you have reached puberty, this does not mean that you are “ready” for the potential consequences of teen sex, which you may be unprepared to handle.

Sixty-seven percent of teens surveyed who have had sexual intercourse wish they had waited longer. Of those who have had sex, more than one-half of teen boys (60%) and the great majority of teen girls (77%) said they wish they had waited longer to have sex.
Source: The National Campaign to Prevent Teen Pregnancy

Know that you are worth waiting for! Believe this, because when you do, you begin to understand that your sexuality is something to cherish and protect and that your personal dignity should always outweigh any pressure to engage in an act that you are not prepared for. Responsibility means that you are mature enough to look at the risks of a decision before you engage, waiting until you are physically, emotionally, intellectually, socially, and financially “ready” to handle the potential consequences of that decision.