Hi and welcome to beyond blue.
There is no right or wrong answer here. I guess if I put forward your story, what would say to me?
I was working at in another company some time ago and there was a new employee hired. Before being introduced to the new person someone quietly told me he was gay. I just said "OK" but in my head I was thinking to myself so what! An extension of this is that won't determine how good or bad they may be at their job they were hired for. Perhaps... we are people first.
From that perspective I don't need to know.
On the flip side... Is this a concern to you? That people in your workplace do not _really_ know you. Or do you feel that you are not really yourself in the workplace?
If you do a google search for...
telling your workplace you are gay
you might find some of the answers you are looking for and things to take into account. (You seem a smart person and would know what to avoid :) and on the 1st page of results there were a few articles I read.)
I cannot imagine it would be easy for you and in making this decision and if you want to discuss this more I am here.