The function of sex
Sexual intercourse between a man and a woman has two functions: firstly to procreate; secondly for enjoyment.
Given the number of times people have sex compared to the number of pregnancies, it must be primarily the latter, although the original function of sex was to have babies and continue the human race. Enjoyment, though, includes everything from a fun one-night stand to the deep bonding of making love in a long-term relationship.
Of course, for those who are gay, procreation as such isn't in the picture, but this by no means reduces the value or validity of sex or of their natural sexual orientation.
Sex in a relationship
This is really the best and most secure situation to be in if you are going to have sex. We say this because, although sex can be spontaneous, honesty, trust and emotional security are very important. Unloving sex can leave people feeling cold and even cheap and soiled. You also need to be able to communicate with your partner. This is one of the key elements in sex.
This is most important when having sex, both to avoid pregnancy - unless, of course that's what the couple wants - and to reduce the chances of passing on any sexually transmitted infections (STIs) which may be present, whether or not either partner is aware that they're there.
The condom is the most popular method of the so-called 'barrier methods' of contraception, which works by prevented the male's sperm from entering the vagina and so, potentially, reaching and being able to fertilise an egg. Because it is a barrier method, the condom is also very effective at minimising the risk of STI transmission. This is called 'safer sex'.
Contraceptive pills are available which the girl can take to avoid pregnancy, and these are by far the most popular method of contraception within long-term, stable relationships, though the pill provides no protection form STIs.
When and if you're ready:
You really must say you're a virgin the first time you have sex.
Go really slowly and gently, don't have overly high expectations - Meantime, enjoy your virginity and maybe explore