It really comes down to doing what you want.
I understand the need for community in real life. A support group is a great way to do that. Don't let your current male presentation stop you. Lots of us have gone to out first support group session in male mode. Yes, it's terrifying, but any half-decent group will accept you as you are.
Going to a support group is also a great way to ease into presenting as female. After my first few male-mode sessions, I started bringing a change of clothes and changing to female mode in the single-user washroom. And then, after a while, I started driving to and from the session in female mode.
I can kind of understand your co-workers' point of view. I also understand why it is disappointing to you. You created an expectation in them, and they perceive you as letting them down. The normal rule for transitioning people, and it seems like your co-workers have defaulted to following it, is that you use the name and pronouns that are consistent with a person's presentation.
You may want to consider moving up your target date for presenting as female.
I didn't come out to anyone until I was ready to present as female to them. In several groups it was like, "The next time you see me, I'll be dressed as a woman." In another group, it was more like, "The reason I am dressed this way is..." That approach worked pretty smoothly, and I have been happy with people's reactions. It might be something to consider if there are other groups you still have to come out to.