I don't tell unless they ask. I only say I'm trans to those close to me, which would be mi family, mi only friend and my partner. Of course, people who knew me before know, but they never say a world about it. Some of my classmates still refer to me as a male and use my old name, but I never had time to engage in a serious conversation to come out to them. THere are a few classmates that play at the orchestr with me. They must have noticed the name change in the programe. They all treat me as a girl, never had any problem with that.
My answer would be proud, but not necesarily loud. I found out this way that a lot of people take this things as something natural. Like "He is a she now, let's have a girls talk".