Why is mum being like this?

No one is willing to tell the truth on here, they only bullshit. This, this, and that, bla, bla ,bla. I think the reason as to why you Mother treats you that why and not your elder siblings, is because your her favorite. Your the youngest, and you actually take responsibility for you actions. Therefore, she expects more from you. Have more respect for yourself, and your Mother will do the same.