I've been doubting if I shoukd reply here because I'm not stealth at all and I don't think I could be 100% at this moment even if I wanted. But I'm just going to deposit my experience with being fully out (by choice, I was there under my new name and I tend to pass mostly) at school.
I'm pre-topsurgery and on T since June, my voice dropped some before I started school and even more during the first weeks.
When I started nobody really doubted I was male, sure a feminine, small male but they had no reason to think I wasn't since I was Nathan and considered male by the staff and myself. I wanted to see how it felt to be Nathan and not tell anyone about being trans, and I didn't really like it :p I felt I had to hide myself all the time, at sports I couldn't explain why I got out of breath easy, I felt uncomfortable in the bathroom, I felt I couldn't share my (really exciting) changes on T, had to omit the truth about not being at school for my endo and psychiatrist and so forth.
I had experienced an amazing freedom after starting to live as me and I was more capable of forming friendships without that wall : now, it felt I was back to pretending and hiding. At the moment being trans is part of my experience of life, at several moments it becomes important. I feel uncomfortable 'having to hide' that.
So I came out, slowly at first to one person because I was really out of breath after biking and talking at the same time with her. I simply said: I'm wearing a binder because I'm transgender and that's really constricting my breathing. Two or three questions and answers and we moved on. Slowly I told more people and finally came out to everyone when I wanted to ask my teacher (healthy diet) a specific question about my situation with a mixed physical state. I asked it in the group because I didn't feel I had to be all secretive about it.
And sure I answered questions and gave some more explanations. Every now and then I'll get another question that shows they've thought about it and sometimes they show that they know and that they care about how I feel (example: We were roleplaying and I was given a case were the character was a girl, my partner said I should just use my own name because he thought it's probably not nice for me to even play a girl at the moment). I don't mind that actually, to me it's just that I have a particular situation at times and my friend care and are sometimes curious.
Now I don't feel I'm not seen as a guy. Sometimes I slip up and forget as a guy I shouldn't do certain things like heartily agreeing with how horrible periods are. At those times I get this weird look and then the 'AHA'-moment :p I get called buddy, dude, mate... Nobody slips up. I am very open, I complain about my binder, I brag about stabbing myself for T :p I get excited about getting facial hair... I personally feel absolutely accepted as me, being trans simply is a part of who I am as a person. Sure I'm just a guy, but hey, I don't feel like pretending my history hasn't been different then that of some others. It gives me freedom.
I guess you have to decide what you want from the situation. I'm definetly not saying my way is the right way for everyone. I also consider myself lucky with awesome classmates and I'm in Belgium which I consider pretty accepting. I valued complete freedom over the risk of being seen as 'less' male. I'm sure they do see me differently now then before. I've just decided that I don't think this different is bad different.
Also the men still totally don't care that I'm in the bathroom with them (even keep talking with me through the door sometimes, I thought guys didn't do that?

), and make dirty jokes about penises and women :p