pixellet I think we over think this. What will people think? What if they stop being friends? etc etc.
The important thing is to stay true to yourself. Always! No matter what! If people stop being friends because they have some prejudice against Trans people, its THEIR problem not yours. A true friend will accept you the way you are.
While I was out as gay in my circles, I was hesitant about revealing the trans bit initially. But I was pleasantly surprised to see the level of acceptance once I started coming out.
Be warned though - some guy friends can start showing a little too much attention once you come out as trans. Don't encourage it too much! Tharakipana is not "supportive".