I had 1 beer 6 hours ago, is it ok to take my proscribed 1mg ativan?

Not a good combo in the long run, best to inform would be your prescriber as you probably take other meds as well that may interfere with both alcohol and ativan.

Alcohol is a poison that never did anybody any good, ever, so stay away from it. It will destroy your brain cells, facilitate development of cancer in many organs, including breast, cause hepatitis, cirrhosis and pancreatitis etc. There is no safe level of alcohol intake. Quit while you are ahead.