3rd Generation here - I remember the day I told my mother - it was the scariest thing I have ever done in my life. I had been wanting to tell her for a couple of years and everytime I thought about it, it made me sick...literally.
By the time I told her, she, too had a clue. Afterall, I hadn't been going to meetings and to make a long story short, I had a baby out of wedlock (now, that was a scary conversation, too!) But, after it was all said and done, it was the biggest relief to have it out. The monkey was off my back. I lost 50 pounds of emotional weight I had been carrying around and only wished I had done it sooner. The worst part was over and now 25 years later, we all go about our lives, mom/family still trying to "save" me and having hope of everlasting life on paradise earth with her/them and I just let it go in one ear and out the other and change the subject.......
My thoughts are with you, trust me, the moments leading up to telling them are the worst, it all gets better and better after that. Nothing is as bad as our imagination.