If you're not sure if you're an alcoholic, try stopping drinking for a set period of time and see how it goes. If you're not an alcoholic, it won't be a problem at all.
If you are not able to stop drinking once you start and you are blacking out frequently, those are signs of alcoholism, but it's up to you to decide whether or not you need to stop drinking. And, keep in mind, that alcoholism is a progressive disease, and it will get worse.