My egg fully cracked the week I started a new job (just hit my 1 year anniversary too!), which was definitely a fun time to come to terms with it. But I realized really quickly that the longer I waited the harder it was going to be, especially after realizing just how painful it was to have to "put the shell back on" in a sense when going into work. I came out right after our holiday shutdown, spoke with my HR Rep about the situation, and it was honestly not an issue whatsoever. Their biggest concern was if I was changing my name, but that was about it. They sent out a really basic email to the team and suppliers I work with basically saying "Your colleague hovercat is transitioning and will be going by she/her pronouns." and that was basically it. It was quickly discussed in the team meeting, they sent everyone a training on gender identity, and that was it. I've not had any real negative reactions with anyone yet, and it's so, so nice getting to just be myself.
There's another trans girl I work with who I also asked for advice, who transitioned after being at the company for a while, and it seemed that almost all of the friction she's had was from old teammates that knew her pre-transition. They were the main ones that caused any issues, and seems to be the story I hear quite often of people taking way more issue with the actual transition rather than the person being trans.
I know it's really scary, but from a lot of the experiences I've seen, it seems far better to just bite the bullet and go for it. Waiting only makes things worse.