It sounds as if everyone is going to find out at some point right?
With your mom, well I guess you will get to a place in transition that she will no longer be able to deny it. I had trouble figuring out how to deal with my mom also. I never really knew her until I was an adult. The grandparents who had raised me had known, and they had passed away long ago anyway. My older brother was the first family I told and he surprised me with, "I would rather have a live sister than a dead brother." Not that we talk much now or at all really but at least he said that. I was going to tell my mom but she went into the hospital a week before I started hrt and never woke up. I do wish that I would have told her. She may have been wondering about me, everyone was at the end. I even asked what she was going to name me if I had been a girl, but I never told her. Anyway, I cannot imagine that you can transition without her knowing but you can pick your time.
Work was not fun for me but the real confrontational attacks happened before I came out. Just the change in me I suppose, I was pushing it in everyone's face if I am being honest, I needed to get it out. After coming out it dropped way off until it was impossible not to see that I was changing, then it got much worse until I left. Not name calling like before, not to my face anyway, but acting like I didn't exist and the constant jokes about me. You may have to pick your time again and may have to be prepared to leave. If you trust your Human Resources, you may want to start there.
There is no rhyme or reason and no way to tell who will be okay and who won't. Who will say they are okay but really aren't or the ones that stand off for a bit but then realize that they don't care. You will try to predict it but unless you are waaaay better than me at that sort of thing, you will be wrong at least some of the time. I had two older sisters living in the apartment below me, one hated me for whatever reason and the other we did stuff all time, cards, cooking, baking, tv. After I told them the one that hated me started to talk to me and her sister, my friend for over two years, never spoke to me again. One of the guys at work that called me such awful names before I came out apologized and was almost my defender after.
This is usually hard for all of us. There are a few that everything is shiny happy when they come out and that is wonderful, but I am guessing that most of us have struggled through what you are now. Take your time if you have to. For me it was the pressure of needing to get it out versus the fear of, well everything really. Eventually the pressure won out.
Be safe and good luck.
