If you are gay AND it is safe to do so AND you're ready for people to know, then yes, you probably should. Coming out makes it harder for people to pretend homosexuals are too small a minority to warrant attention to claims of discrimination and to counter the perception that we're all easily labelled. People almost always get more accepting when they know someone gay who breaks the stereotypes they are familiar with.

There is no need to say. I'm gay and I never do unless it comes up in conversation. Why does anyone need to know otherwise?

Though if you're going to do it in English, your command of the language needs to improve.

?????

Maybe you need to ask this in the section of this site for whatever language you're fluent in. Nothing you say makes any sense.