Why am I having issues with my mother?

My mom behaves in a very odd manner about things which are actually not such a big deal. Before I begin, my mom is a single mom and I am the eldest of 3 siblings (this should give some perspective to my question) I am 22, in my last semester of college and my mom still dictates that she wants me in bed by a certain time. My mom asks me to wake up early however I have tried and it is so very difficult for me to wake up that early for her, and for this reason I have also scheduled my classes later in the day so I have time in the mornings to wake up and not feel rushed. I study or perform better later in the day. I am also trying studying for my graduate school exams and she keeps asking me to wake up early, study and then go about my day and I am scared to tell her that her was will cause me failure and if I try to do things my way, I am scared she won’t approve and then I will feel upset for making my mom unhappy. We live in a one story apartment and all I do is sit in the living room and try to study and complete my assignments once she goes to bed with my siblings because I am unable to finish my work during the day. In my culture, it is not looked well upon for children to move out and so I would never think about moving out (since I know a lot of people my age would move out as an answer to this problem) however it really upsets me when my mother takes matters like these and makes it into a big deal. I do not handle stress well and well, my mom does not want me sitting outside in the living room and studying and she makes the situation very tense. I respect and love my mother very much however she just does not understand my preferences, my work/class schedule and the reasons behind the decisions I make. I am a person who needs my mother to be happy with me and understand me however I feel as if my mother will never understand me for who I am? Am I wrong to be overreacting to something like this or does every mom behave like my mom does with her 22 year old child.