hey Lauren, I'm exactly where you are. In fact, Monday, I'm going for my initial blood tests prior to HRT so I'm psyched.
Regarding transitioning on the job, when I started my job about 2 years ago, I started growing my hair long. It was slightly long boy length at first and then eventually, I got into wearing sunglasses to keep the hair up and now I just wear it in a ponytail. I've never let my hair down in two years at work.
No one asks, but if they do, I just say I want to look like the guys in Lord of the Rings, esp. Gandalf. They all had long hair.
Long hair, unless it's hazardous in your job, will probably not be an issue. I see rough and tumble guys with long hair everywhere I go. As long as you keep it clean, it should be fine.
During these past two years, I did all my facial hair removal and voice training, while establishing myself as a hard and dedicated worker. I don't play politics at work, I don't surf the net or use personal email, I just work and my boss knows it.
I think transitioning at work is helpful if your bosses value your work. If you can establish that respect and value, it might be easier.
Also, during this time prior to HRT, i've slowly trimmed my brows. Either no one wants to broach the topic, but my therapist tells me I look very female without makeup. I say tish tish and believe that I am still one of the guys, but, the trimmed brows have got to be a give away.
Anyways, depending on the job, if you're very skilled and work hard, you're an asset to your company, and in this day and age, I see a lot of workers slacking and abusing their computers and phone use.
Finally, I make no illusions as to whether they'll accept or reject me when I finally have to come out. I've made no major purchases such as new home or new car and have been saving cash like mad, so if I'm forced to leave, I'll be able to weather the time between jobs.
So yes, you can do it at work, but do as much as you can before the hormones. You'll want to get your finances in order as much as possible. Being in debt sucks, being in debt and trying to transition sucks even worse.
I'm opposite of Kate. I look more male with my hair up.
In the end, I think it's how you establish yourself at work. I would like to think that most bosses don't care about your personal sh*t, as long as you do your job. If you do it well, then that's a huge plus in their opinion.
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I'm not sure where you are with facial hair, but I would recommend getting that taken care of first before you do HRT. I have light facial hair, but it's taken almost a year to get it 85~90% cleared.