Before coming out to someone, the very first thing I recommend you to do is to think about how open-minded that person is.
Anticipating what kind of reaction you might get can make things easier in the long run.
If it’s a person that you know well, and that is important to you, it might be easy for you to know what to expect.
So the closer the person is to you, the easier it is to determine if you should or not come out to that person.
If you are still insecure about who you should tell about you being a crossdresser, consider doing so with someone that you have an extra trust, and who’s not likely to spread that secret.