Run away from sexual immorality [in any form, whether thought or behavior, whether visual or written]. Every other sin that a man commits is outside the body, but the one who is sexually immoral sins against his own body.
1 CORINTHIANS 6:18 AMP
This is another verse that clarifies that premarital sex is a sin. This verse also indirectly states that masturbation and watching porn is a form of sexual sin.
No matter how we try to justify premarital sex, it is a sin. It is not greater than telling lies but it is a sin. Obey God first by abstaining from it, and trust God to help you achieve a fulfilling sexual life when you get married. If you are single, you can start now to pray and tell God what you want. It’s better to pray about it than to act on your sexual desires outside marriage