Grad school isn't the worst place to transition as long as you have a supportive advisor — which I do, fortunately. I came out via email that was basically "I'm a girl now, here's my name, if you have questions let me know, here's a couple links to read if you want" that I sent to a bunch of folks who knew me.
Certainly now there are plenty of people I work with who very much aren't okay with trans folk, but most of them have managed to be respectful, whether because they think Title IX applies or because they understand how to be decent people or because I'm the oldest student in the lab and my advisor expects them to work with me.
I did lose a few friends and mentors over transitioning but I also gained some new ones. While some folks certainly are less comfortable around me, other folks are more so! And if I'm making other queer students and women more comfortable existing here, I think I can be content with that.