I'm transgender, do I really have to come out to my family?
Is there something preventing you from coming out?
My family will hate me, they'll reject me
Your gender identity is your own and you don't owe anyone an explanation or definition of who you are. If you think they will react negatively and it will impact you in a harmful way, then it's reasonable to not come out to them. I hope you have someone in your life you trust with your true self, but everything regarding coming out is for you to decide and should be done on your own timeline. There is no right or wrong way to do this.
What if I just lie to them too? I've done it for a year now with no problem.
I personally would not equate keeping this to yourself as lying. And if you know they will reject you and treat you unkindly, then frankly they are the reason you can't be open with them about being transgendered. That's on them, not you.