Salam, my family claim to be Muslim but unfortunately have a bad lifestyle and mindset (no religious practices whatsoever) however I am not like that and if I choose to cover my awrah, my mother seems to get very upset at this situation, she says if I were to put on the hijab, she would disown me. So I hide all my thoughts, I hide praying, I hide going to the mosque, I hide how much I am into my religion because she is the opposite and always argues with me about this. Would you advise me please.
That is a a difficult situation to be in and I hope things will get easier for you. One thing you could try is to gradually increase your practicing of Islam so that she has time to adjust to it. Maybe you could start praying without trying too hard to hide it. She may get used to the fact that you pray regularly and may stop complaining about it.
Just because she says she will disown you if you wear the hijab does not mean that she is really prepared to do that. You could do your best to dress modestly, and perhaps wear a cap outside that hides most of your hair.
If necessary, you can wait until marriage to start practicing Islam fully. God does not ask you to bear more than you are able. Try to seek a balance between practicing as much of Islam as you can while keeping conflict with your family at a bearable level.