If you are definitely going then my advice would be to let a good amount of friends know that you are not drinking anymore so that even if you do feel the urge, you'll also feel a sense of sticking to your word and not looking like you have no control over yourself. Secondly, make sure you have a non-alcoholic drink in hand at all time. Eat a lot and make yourself full. Remind yourself that you don't want to go backwards. Finally, do it for your mother. She would want you to be healthy and living your best life. Maybe you will find some sort of harmony being there, although I suppose you won't know till you are there.