I have a Netflix account and haven't told my family.
Why do you think that you need to hide that from your family?
If my family finds out they might tell me not to watch movies.
I understand why you want to hide this from your family with your situation. Overall it's wrong to hide things from your family, you should try to have a discussion with your family on why you have the Netflix account. If you continue to hide it they may eventually find it and punish you for it.
You should come over and I will show you how my family's hobby of yelling at me works.
Yelling at you is not going to get them anywhere, so I think that you should just tell them. You pay the bill so hiding that from your family is just going to look bad.