I think I responded to your thread about your girlfriend and I am glad that you want to try to help her.
The only way you know if you are one of those people that can drink moderately is to try it.
If you can just have a drink or two and not want anymore and not really care when you have the next one then you are probably a normal drinker but if you have to keep drinking even after you have met your preset limit you probably can"t or even if you are really annoyed by having to call it a night moderation will probably not work for you.
I am pretty sure that everyone with a drinking problem has tried to drink moderately. I know I have a few dozen times.
Good luck with your girlfriend. It is obvious you care a great deal for her.