Timing is everything when coming out. I told my family pre-HRT and regretted it pretty quickly. I began getting objections and everyone was trying to convince me to wait for HRT until I could be "saved", for instance. I was clear that I had already made the decision to move forward, but everyone got so immediately upset that I was making my own decisions that it just added to my stress level.
Telling them after a couple weeks (or more) of HRT would, I think, have made it less stressful for me. I could have honestly said to them that since I'd been on HRT, I was more certain than ever that this was the right path for me.