If you feel you're under pressure, here are some possible answers you can give if you feel you are not ready to get involved on this level:
Her: But everybody’s doing it.
Him: Everybody’s not doing it. A lot of people decide to wait, or pretend to be sexually active to impress their friends.
Him: If you loved me, you would have sex with me.
Her: If you loved me, you wouldn’t expect me to do something I don’t feel comfortable with.
Him: I won’t have sex with a condom.
Her: Well, I won’t have sex without a condom.
Him: I’ll die if I don’t have sex.
She : No, you won’t. Sex is nice, but it won’t kill you if you don’t have it. Many people live for years without having sex.
Her: No-one will ever know.
Him: I’ll know and that is enough. Besides I don’t want to do anything that must be kept a secret.
Him: You cannot get pregnant the first time.
Her: Oh yes, I can. Many girls have fallen pregnant when having sex for the first time.
Him: If you won’t have sex with me, I am going to leave you and find someone who will.
Her : Well, if that is all that this relationship is about to you, I’ll be better off without you.
Her: It’s my right to have sex.
Him: And it is my right not to have sex.
Her: You don’t care about my needs.
Him: You don’t seem to care about my feelings, if you are happy to let me do something I might be unhappy about afterwards.
Him: So, you are not interested in sex. Maybe there is something wrong with you.
Her: Of course I am interested in sex. But it won’t feel right for me to do it now with you. - (Susan Erasmus, Health24)