Yes, once your sister becomes a US citizen which may take 3, or more years, she can sponsor your mother. Then, yes, your mother can sponsor you. If you are unmarried, it is currently taking approximately 7 years for that sponsorship to be of value. Thus, your plan, if things go smoothly, will take 10, or more, years. You may find it beneficial to talk to an experienced immigration lawyer.
Answered on Nov 18th, 2011 at 2:32 PM