If my mother is a resident, can she get a petition for me? What would we need?

As an LPR, your mother can file a Form I-130 petition for you. And I strongly suggest that she file the petition right away before your 21st birthday. Please understand that there are several issues involved in the process of getting a green card. You should seek the guidance of an experienced immigration attorney.

It will be very difficult for you to legalize your status now that you are over the age of 18. If your mother never petitioned for you, she can petition for you now but once you turn 21, if you did not enter the U.S. lawfully, under the current immigration laws, you are not eligible to legalize your status within the U.S. How is it that your mother has a green card and you do not? Why were you not included in her application when she got the status?

A green card holder can file a petition for their unmarried child. Once filed, it puts you on the quota waiting list. That's the first step the rest is likely much more complicated if you're currently out of status.

Yes, your mom can petition for you. However, there is a long wait for a visa and you would have to leave the country once the visa becomes available if you are not here in a legal status. That could trigger a bar from the country for 10 years. You should check if you qualify for DACA. Talk to an attorney about that.

Your mother can apply for you, but the process takes years. For instance, if you were born in Mexico, you will not get a green card on your mother's petition for about 20 years; if you were born in the Philippines, the soonest you might get a green card will be 11 years from the date when your mother would file the petition. And you will lose the ability to get a green card through your mother's petition if you become married. If your mother could become a citizen before you turn 21, her petition for you would move through the system much, much quicker. However, the problem with your illegal entry in the U.S. will be an obstacle to your legalization even if your mother becomes a citizen. I recommend that you should discuss this problem with an immigration attorney so he or she could evaluate all the facts in the case and tell you what are your chances of receiving a pardon for your entry without inspection and your illegal stay in the U.S. for all these years (this pardon is called "waiver") Another subject you should discuss with an immigration attorney is whether you could apply for work permit under the program called DACA ("Deferred Action for Childhood Arrivals"). If you receive DACA, it will solve many of your problems. Finally, it might be possible to obtain the special immigrant juvenile status for you. It is never simple, but it might be possible to do in your case. After looking at all the details of your case, an immigration attorney would be able to tell you which of these programs you can qualify for, and which one is the best for you.