I'm sorry that you feel your family will not accept you fully. I hope it turns out better than you expect. I actually thought my parents would disown me. However, they have been very supportive. My mom even takes me shopping and sends me clothes. My dad is trying his best to use my new name, and my stepdad is trying to use female pronouns. I mention this because, for me, it is a good example of how people can react very differently than what you expect.
Let us know how it goes once you do tell your family.