Glad you are here. Try reading the stickies for more information.
What you are intending to do is tough on everyone. Having said that, it is best to be clear about how her alcoholism has affected you - the use of clear examples help to present your case.
I hope you understand that your own response may be difficult if you do not get the response you expect. Be prepared to tell her the truth from your view point. Be honest but not degrading. She has a serious illness and your views may or may not be heard by her but it is important to voice.
I hope your family has consulted with a professional on this. It requires preparation. In the mean time, be educated on her illness. Take responsibility for yourself and allow your mother to take responsibilitiy for her actions.
I too had an addicted mother who died from it twelve years ago. I spent a life time covering for her, keeping secrets and feeling on the outside of life as a result. I did not learn anything useful until I let go, got honest and stopped lying for her. I will keep you in my prayers. Be strong for you.
hugs