Instead of State sponsored skilled migrant, your mother can sponsor you on a 489 Family sponsored visa( addtl 10 points if you cannot met the 60 points threshold for 189 or 190 visa.) This is a provisional visa that allows you to live and work in Australia for 4 years and have the option to apply for PR visa after meeting the req. of 2 years stay and at least 1 year fulltime work. This means that you still go through the process of skilled migration application.