At first, I wasn't going to tell anybody except my immediate family. Then I realized that I didn't really care if other people approved. I didn't do it for them. So I told anybody when it came up as to why I would be missing from work or better yet, shrinking. Luckily, I guess, I got almost exclusively positive feedback.
Do what makes you comfortable. On one hand, it's none of their business. On the other hand, if they are not supportive, then they are probably not worth your effort.
Plus, if you ever need support, I find just hanging around this site does wonders. Good luck.