Eligibility and formalities for Family Visa

Welcome to the forum

I may be wrong but I think your sister needs to have citizenship. You should check out the immigration website for latest information.    www.immi.gov.au

There is a lot of responsibility for whoever sponsors you. If you get into financial difficulties or police problems then they are liable and may also end up in them being asked to leave the country along with you.

Work permits are issued by your employer if you are successful in getting a job.
Age group is a concern but depends on your field of expertise, formal and educational qualifications, and work experience.

There is a skills list which gives a list of jobs which get preferential treatment for visa and permit applications.