It's different for different people.
One thing most have in common is that it becomes harder and harder for the alcoholic to "keep it together" or at least the APPEARANCE of "keeping it together". They start screwing up and it becomes harder and harder to hide it. They might get really defensive, making up BS excuses for why this or that went wrong, when it is really the fact that they are losing it.
Some people get physical symptoms quickly, and some get very few for a long time. A lot depends on the individual--her overall health, for one thing.