It's possible that it is vitiligo, but it could be something else, too. Certain rather common fungal infections mimic vitiligo very closely, but you can oust them with some antibiotics and regain the "lost" pigment.
If it is indeed vitiligo, the earlier you diagnose it and start to treat it with narrowband UVB, the less likely it is you'll end up looking like Michael Jackson, who incidentally also had the ailment. I have it, too.. had it for over 2 years now and I've lost some pigment here and there. Nothing major yet. I'm trying to save up on a full body UVB cabinet with which I could treat myself at home.
Even if it is vitiligo, there is a chance it will turn out to be the kind that is localized to one area of your body; where it will remain. The slightly more common form of vitiligo, generalized vitiligo, will likely progress to cover more areas of your body, though (unless treated).
Sadly, as of today there is no cure for vitiligo and it is generally a disease that progresses throughout one's life, or at least for several decades. It is documented that elderly vitiligo patients who have had the condition for a very long time eventually experience a halt in its progress. There are also some documented cases of spontaneous reversal of the condition, reactivation of the dormant melanocytes and full repigmentation. This can perhaps be induced by the right dietary and supplemental choices, but I don't know how that can be done.
Anyway, let's hope it turns out to be something else instead!