If I drink alcohol will it do any damage to my brain?

Im 16 and i've heard of people even younger then me that drink alcohol. I have always been weary of alcohol because I know its bad for you and can cause brain and liver damage. Then I read online that alcohol in moderation can actually help your heart. I know it is bad to drink alcohol if you are under 25 because it can cause permanent damage to your brain, but will it do any bad or long-term damage since im 16 if I just have one small cup?