What God says
If you are not married, God says you should abstain from sex. Why? Because God designed sex as a covenant act between a husband and a wife, a gift of intimacy with the person you have chosen to spend the rest of your life with. It is a physical act and a spiritual act and the only safe place for it is marriage. So, even when you are in your 30s and still single, you are called to refuse to have sex until you marry.