It takes time and its normal not to be sure. Experimentation is natural - as long as you look out for the safety of yourself and others. You may want to date the individuals of the opposite sex or you may decide to date those of the same sex. Exploration doesn't determine your sexual orientation, it just helps to discover your feelings. You don't have to have sex to know if you're heterosexual, homosexual, or bisexual.
Some people never have sex in their entire life, but they know their sexual orientation.
It's better to wait until you're emotionally ready and you find someone you care about. Sex can create more confusion then it can resolve. There are many ways to share intimacy with someone you care about, such as talking, spending time together, hugging, kissing, massaging, and holding hands. If you decide to have sex, it is important to remember to protect yourself and your partner and practice safer sex. Some people recognize that they are homosexual early in their lives while others do not become aware of their own gayness until much later in life due to the many pressures society puts on us to follow a heterosexual lifestyle.