Questions about Green Cards?Please Help?

you can't sponsor your family until you turn 21. you can choose to file an I-130 for your mother at that point, and not your father. your father can't file for an immigrant visa on his own. while you can file for your sister at that point as well, it will take 11 years before that petition becomes valid for use. your mother could come over, get a green card and then file for your sister and if your sister is still under 21 at that point, that petition would currently take another 3 years. so, there's no quick solution for your sister.