From what I've read, blackouts have more to do with your BAC and how quickly it rises. So it's not just how much you drink. Things like having an empty stomach or drinking the same amount but in a shorter amount of time factor in, too. (Also, having them in the past makes you more likely to have them in the future).
Alcohol damages the brain, for sure. I noticed a definite improvement in my thinking once I got sober. The sooner we stop the better, of course.
Glad you're here, Jade!