I am glad that you are considering using protection. A condom is a barrier method of protection. This is preferred because it protects against getting STI and UTI's. Birth control pills and Plan B [emergency pills] are all of hormonal based products where the first prevents an ovulation, while the other prevents an egg from implanting on the uterus wall.
Hormonal products can be effective too, but they do NOT provide protection against STI or UTI. They do however have side effects. Consider your options before proceeding further.
It is also important to be sufficiently wet down there, or penetrative sex can be very painful on a dry vagina. Learn to say NO if you are not well lubricated. Spend time during foreplay
A word of sincere advice - most girls your age regret losing virginity too early in their life, not to mention their sexual organs are not that well developed, so, they do end up having pain during sex. Good luck
PS - STI - Sexually Transmitted Illness, UTI - Urinary Tract Infection