Are you Nightkin? It's a fairly easy question. Here are some questions you can ask yourself in return, and maybe come to your own conclusion.
Does night evoke something reverent in you?
Do you feel more awake at night than at any other time?
Does the sun somehow always seem to dim your gifts, and if you're a beginner, does the sun make you a tad uncomfortable?
Do you often find yourself sitting outside at night for no apparent reason, just gazing?
Are you more comfortable wearing dark colors?
Do you identify yourself as good, but just... dark?
Are you often misunderstood as being evil?
Do you feel the night as a tangible presence?
Are you more drawn to the darker gods and goddesses?
Ask youself these questions. Go to your local bookstore and pick up Konstantinos: Nocturnal Witchcraft. Sit outside at night and just feel your reaction. You'll know soon enough- it may even find you.