I doubt if there is an appointed time to have sex in a relationship. Humans are not robots and the feelings vary depending on the foundation of their love.
@theoneIke once said that Marriage is the only sexual relationship that God ordained in order to complete the task of procreation as ordered. The church created Courtship in which sex is not encouraged however a lot of counsellings and all to help you both study each other well. Mankind created Dating in order to make it social and easy for people to have the aura of relationship which encourages sex and all such that people can "know themselves fully before getting into marriage"
According to Wikipedia: Dating is a stage of romantic or sexual relationships in humans whereby two or more people meet socially, possibly as friends or with the aim of each assessing the other's suitability as a prospective partner in a more committed intimate relationship or marriage.
What really gets me exhausted is how Christains say they are Dating when the principle of dating in itself encourages sex.